Garden Myths - Learn the truth about gardening

Pond Pumps and Pond Filters

About 7 years ago I started developing various water features, both garden ponds and water falls. As part of my research I found consistent comments like the following:  you can’t make a natural pond using a pond liner without pumps and filters. The use of the word ‘natural’ here refers to the pond filtration system, not the esthetic look of the pond. I’ll deal with esthetics in a future post on how to build ponds.

In a natural pond the water, soil, plants, and animals all live in harmony. No one comes along to clean the pond or to aerate it. There is no big man-made filtration system that keeps the water clean. The common advice is that a pond liner is artificial and a pond built with it will never reach a natural state where the water, plants, and animals live in harmony the way they do in a natural pond. If you don’t filter such an unnatural pond it will become full of algae and the water will be dirty and smelly. The only way to have a pond with a liner is to add aeration and filtration.

Is this really true? Do you need pumps and filters to provide artificial pond filtration?

pond pumps and pond filters

Author’s pond at Aspen Grove Gardens (1 st year)

Building Natural Ponds

This blog post is the second most popular post ever on this site. Lots of people comment and are interested in more information about building natural ponds, so I have started a public Face Book Group to make it easier for people to discuss this hot topic. Please join the group at

Building natural ponds face book group

Building natural ponds face book group

What Happens in a Natural Pond?

In a natural pond animals (insects, fish, etc) eat, poop, sleep and die. Both the poop and dead animals add nutrients to the water. Some is added immediately, and some is added over time as the material is degraded by various micro-organisms.

Plants also add nutrients when they die. In fall all kinds of leaves and other dead plant material is blown into the pond, and as this material is decomposed by micro-organisms it also increases the nutrient level.

Algae is a plant that grows best with high light and high nutrient levels. When the nutrients get high enough, the algae takes over the pond and chokes everything else out.

Why does the algae not take over natural ponds? The answer is higher order pond plants (not including algae). Plants also use nutrients and as long as the plants in the pond use up the nutrients as fast as they are produced, algae has trouble getting a foot hold.

The secret to an algae fee pond is to control nutrient levels!

The other important part of a natural pond is the presence of micro-organisms. They are everywhere; in the soil, on rocks, and attached to plants. Think of these micro-organisms as the ‘cleaning machine’ of the pond. They take rotting, smelly animal and plant material and turn it into nutrients that plants and algae can use. The micro-organisms keep the water clean, and keep it from smelling.

A man-made pond made with a pond liner has no soil – so one source of micro-organisms is missing, especially if you keep cleaning the pond liner. Most ponds have few stones and few plants reducing the number of micro-organisms even further. Without microbes or filtration, the dead animals and plants just sit in the bottom, making the water cloudy and smelly. But it does not have to be this way – read on.

Controlling Nutrient Levels

There are a number of ways to control nutrient levels:

1) Don’t add too many fish. Too many fish results in too much fish poop. Koi poop more than gold fish.

2) Don’t feed fish. There are lots of natural things for the fish to eat. Adding extra food just adds more nutrients to the pond.

3) Have lots of living plants in the pond. With enough pond plants growing, they will remove the nutrients before the algae can grow.

Most man-made ponds are not designed to hold a lot of pond plants. Without the plants you need to add some type of mechanical filtration system.

how to build a pond or water features

Adding the pond liner to a water feature at Aspen Grove Gardens

The picture shows a pond at Aspen Grove Gardens during installation. The black pond liner is in the deep part and the planting shelves are covered in carpet (white/gray areas). The liner will be pulled up to cover the carpet.

Note the extensive size of the planting shelves compared to the total size of the pond.

Why Aerate a Water Feature?

A natural pond has no obvious aeration. There is no hidden pump creating air bubbles. So why is it needed in a man-made pond?

A poorly designed man-made pond does not have enough plants, and it does not have enough places for micro-organisms to live. As a result, dead stuff accumulates on the bottom. As this dead stuff starts to rot it uses up oxygen, and the water at the bottom becomes depleted in oxygen, which in turn causes anaerobic bacterial to grow. This type of bacterial loves the smelly mess and they thrive with low levels of oxygen. This seems like a good thing, and environmentally it is a good thing. The problem for us is that as they digest the rotting stuff, they make the water smell. We don’t like smelly ponds even if they are natural.

How do you get rid of the anaerobic bacteria? Simple, increase the level of oxygen by pumping air into the water.

Aeration is recommended for ponds so that they don’t smell and that works quite well. The problem is that without anaerobic bacteria, the sludge on the bottom degrades very slowly and so you also need to clean the bottom of the pond on a regular basis.

Think about this. Because you bought a pump and you aerate the water, you now need to do more work and clean the bottom.

Do Natural Ponds have Smelly Sludge at the Bottom?

Sure they do. It is quite normal to find this in a pond where a lot of animal or plant material falls into the water. You don’t normally smell it because the water is not stirred up enough to move the smells to the surface. Dig around with a shovel or step into it from a canoe and you’ll find the smell. The smelly sludge on the bottom is natural.

My man-made water features have sludge and anaerobic bacteria in the bottom. If I don’t disturb them, they degrade dead plant material, and produce nutrients for growing plants. In my ponds I don’t stir up the water so I don’t smell them.

Pond Filters

Virtually every reference on building water features recommends some type of filtration system for a man-made pond. Why is this necessary?

As mentioned above, the lack of soil in the bottom of the pond and the lack of rocks and plants results in an environment that houses few micro-organisms when compared to a natural pond. The solution is to provide a man-made place for the microbes to live. Most filtration systems contain some type of surface for the micro-organisms to live on. This can be sand, wool, small pieces of plastic – it doesn’t really mater. What is important is that there is a lot of surface area. Microbes like to attach themselves to a surface and then ‘eat’ plant and animal bits as they float by in the water. So the filter replaces the natural places were microbes live–on soil, rocks and plants.

In nature the microbes live in the slime you find on rocks. It is healthy for a pond.

Water Feature Myth

The above information should give you some background to understand both natural and man-made ponds. If you think about it for a while you will realize that a properly designed pond, with enough pond plants and homes for microbes,  should work just as well as a natural pond. When I was planning to build my ponds I spent a lot of time trying to find a reference for a man-made pond that worked without pumps and filters – I found none. Every reference I found said that such a pond will not work.

I set out to prove the experts wrong.

The following is not the result of good research or the opinions of experts. It is the result of my experience with two ponds over a 6 year period. In this blog I am not describing how to make a pond but I will do that in another blog entry–some day. I will provide the key points to consider.

Based on the information above, a pond design needs two things which are lacking in most designs. It needs lots of pond plants. Plants will use up the excess nutrients and keep the algae in control. It also needs lots of little homes for microorganism – they will help keep the water clean.

The following are some key design decisions:

1) Wide planting shelves. My pond is 20 x 30 feet and about half of that area is in the form of planting shelves that are about 8 inches deep.

2) Soil is not used for the plants. Pond plants don’t need a substrate, except to hold them down, and the pond certainly does not need more nutrients from soil. The plants should be using the nutrients produced by the micro-organisms and not the nutrients in soil . Instead of soil, I use small rocks – 1/2 inch or so. I just use all the small rocks I collect as I make new flower beds. Don’t fertilize your plants.

3) Pond plants are not in pots. I just place them on the small rocks in the planting shelf. A larger rock on top holds them in place until they root.

4) The sides of the pond are lined with rocks adding more surface area for microbes.

5) A deep planting shelf (about 2 ft deep)  is also present for waterlilies. It is important to cover 2/3 of the surface water to reduce light getting to algae.

6) Goldfish were added to feed the plants, and eat mosquito larvae . They are never fed. They grow quickly and breed regularly.

The garden pond in the pictures was built 5 years ago and it is only now that the planting shelves are starting to be full of plants. Wild bull rushes seeded themselves the second year. Irises have been added and are spreading. The pond has never been drained, and the bottom is never cleaned. It has no pump and no filter. Wind is the only thing that might provide some aeration as it ripples across the surface of the water. There are several large trees around the pond that add fall leaf drop – which is left to settle in the pond.

For the first 4 years the pond plants increased in number each year. During this time, I did have string algae, but it mostly had a spring bloom and by mid summer it was under control. The water was very green showing the presence of lots of one celled algae, but the water was clean, and it did not smell. The fish that were added the first year did not over winter but since year two they have overwintered and keep breeding. Herons and racoons help to keep numbers in check.

From a naturists point of view the pond is very healthy with lots of frogs and dragon flies breeding each year. Larger mammals, including deer use it as a water source.

It is now nearing the end of summer 2013 and the pond has been extremely clean–much clearer than the picture below from 2012. In fact it is too clean. You can now see the pond liner in the deeper sections of the pond. There was no string algae this year and almost no one celled algae. It has been a strange year weather wise which may account for some of this, but I think it is mostly due to the fact that the planting shelves are now very full of hungry plants which are out-competing the algae.

After 5 years I conclude that aeration and filtration are ‘probably’ not required. I’ll need to wait another 5 years or so to be absolutely certain of this. It is possible that in a few more years the stuff at the bottom will overwhelm the pond and may need to be removed. I doubt it!

Water feature without pond filters or pond pumps

Water feature without a pond filter or pond pump 2012

String algae is gone, but one celled algae is still making the water green in late summer. Note the number of plants in the water.

Water Features at Aspen Grove Gardens

Same water feature as above in fall of 2014

As plants grow and get larger, algae is almost non-existant.

Is Green Water Bad?

From an environmental point of view there is nothing wrong with water that contains algae. In a natural pond it might indicate that too much fertilizer has leached into the pond which is not good. But this is not usually a problem in a man-made garden pond. If your pond water is green with algae it is probably healthy.

You might not like the look – that is a different matter.

In Japan, garden ponds are treasured and it is common to buy a dye to color the pond water. Why do they do that? When the water is colored it reflects light much better. The shadows and reflections are considered to be very desirable. So next time someone comments about your green water, just tell them that you do it on purpose to better enjoy the reflections.

If You Have Questions

If you have further questions about building natural ponds or about your existing pond please post them in our new face book group called Building Natural Ponds.

Beneficial Pond Bacteria

natural ponds do not need to have bacteria added. For more on this topic have a look at Beneficial Pond Bacteria – A Waste of Money.

Related Posts

Water Lilies for Ponds

Winterizing Ponds and Water Features

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Robert Pavlis
Editor of
I live in southern Ontario, Canada, zone 5 and have been gardening a long time. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

I hope you find Garden Myths an educational site that helps you understand your garden better.

260 Responses to 'Pond Pumps and Pond Filters'

  1. I am really happy to say it’s an interesting post. I learn new information from your article, you are doing a great job.

  2. Sheryl says:

    I can’t wait for your book to be released! My hubby & I just bought a farm in western Oklahoma with an already established large “pond”. It has a water fall – pump and filter system. I don’t want to use chemicals as the deer, raccoon, squirrels, lizards, frogs, etc live and drink out of it. Like yours, I’d love to have it take care of itself. I’ve had a hard time figuring out how to make this non-chemical idea work for me though. I love your research and ideas and would like to give it a try. I’d love your input on where to start….please. Right now, it has no fish, its full of green algae and dirty water. We covered it in the fall to keep more leaves out of it. You can see it in this picture:

  3. Thomas Wolfe says:

    Great article. I built four ponds in my sloping backyard two years ago. The ponds flow from one into the next with the top pond having a 3′ water fall, the next two have about a 2′ waterfall each.The ponds range from about 300 to 500 gallons in size. I placed plants in the area around the ponds but plan to add water plants and fish this spring. I plan to put two KOI in the top pond, about 12 small goldfish in the second and the mosquito larvae eating minnow fish in the bottom two. I live in the U.S. in Iowa and will need to make sure my fish and plants survive the winters. The top pond is 4′ at the deep end next to the waterfall and slowly slopes up over a 20′ distance to the shallow end. I plan to build a barrier to keep the KOI in the deep end and keep them from eating my plants in the shallow end. The second pond is about 2′ deep or a little greater and is elongated somewhat like a creek. The bottom two ponds average about 3′ deep each. I have a 10,500 GPH pond pump which draws from the bottom pond and dumps into the shallow end of the top pond with a 6′-7′ rise in elevation. The pump and pipes are completely hidden, not visible at all. The pump runs silently and provides great circulation through the ponds and impressive water falls. The waterfall sounds are really impressive. I have a 2,000 SF house, 3/4 of the roof rain water flows off the back of my house. I routed the gutters to drain, one into the top pond and the other into the second. I never have to top off the water which is nice but I have had a very bad algae problem. I built every aspect of the pond myself and have been struggling with what filtration system to use. I started studying creating a pond system that does not need filtration and your article closed the loop for me. I have water plants on the way here, Jan 2017. I will start them in the house under grow lights then move them to the ponds in the spring. I will then add fish and I’m very excited about the results that I am confident in having. Thank you again for this wonderful article. My e-mail address is if anyone would like to contact me.

    • Great story. You might like to join the Building Natural Ponds Facebook group and share your stories and pictures.

      • Tom Wolfe says:

        I will join, by the way I actually made an attempt to calculate the gallons per pond and it appears my largest one is much more like 1,200 to 1,400 gallons. The others are not too much smaller. Larger capacity than I thought, I wasn’t concerned in the least how many gallons they each had, I was going for what we wanted. When I started studying KOI, gallon size I found out is important for several reasons. Like best population size based on gallons of water and water depth available to them. It’s been enjoyable researching pond fish, their needs and desired water conditions. I’m looking forward to planting water plants and adding pond fish this spring. My grandsons are going to be involved with the process as well. Should be very enjoyable.

      • Salina C. says:

        Hello. I live in an area in SoCal with a lot of mountains so it gets really cold and then really hot (some weather background). And the house I just moved into has an empty man-made pond that is completely lined with big rocks that’s about 5′-6′ long and about 3′-4′ at its widest. So it rained and it completely filled up so it’s about 3′ deep. Mosquito larvae have infested it so I just got 20 minnows and 20 goldfish to eat them. The puddle/pond has been here a while and the rocks already had moss. And I added 2 water plants. And I have orange trees around it where leaves and even some oranges have fallen and there’s brush around it too.
        What should I expect from my fish?
        Are the gonna die quickly or do they have a chance even if there is no water pump?
        Is the water too shallow?
        Also wondering will they freeze? It gets about 40 degrees at night over here sometimes. Thank you.

        • The fish will be fine – why would they die? The minnows may die in summer if it gets too hot – they like cooler water.
          Three feet is lots of water for small fish.
          Add a lot more plants – they need to use up the nutrients in the water. If the pond has not be maintained for a while, you might want to scoop out most of the stuff on the bottom.
          Assuming you are talking fahrenheit degrees, 40 is above freezing – so they won’t freeze.

          You might be interested in joining our Facebook group

  4. Michael Hoffman says:

    Thank you for this site as it’s inspired me to create a pond with my daughter this spring. I live in Maryland and am going to make a 7×12 pond with the intent of making one end three feet deep and the other down to 24-30″. I plan to have two shelves on the deep side and one wider shelf on the other. What do you think would be the best width of each shelf for this design? I do plan to have a a few goldfish as well as some mosquito fish and some bluegill to keep them in check. Any recommendations on the best layout for this size would be greatly appreciated!

  5. Brandi says:

    We have 3 ducks. My husband is very interested in a natural man made pond with a liner but he keeps saying the ducks will eat all the plants and quickly. Do you have any advice or suggestions on plants that ducks are less likely to eat?

  6. Very helpful and informative article. I have been thinking of homesteading for years and when I do I would like to have one or two ponds on my land. I never considered putting in a pond with no liners or filters but you have proven that it could be done.

  7. This post is so helpful! My family just purchased some land in central Florida that contains a small man-made pond (maybe 12 feet by 6-7 ft, about 2 ft deep). The pond has never been filtered before, but through our hot, muggy summer it has become very green and opaque. Everyone that I have spoken to says it needs a pump and filter. I have no idea how the previous owner cared for the pond, but I know he did not have any filters or pumps. I want to return the pond to its former beauty, but would like to do it as naturally as possible. Is this possible in steamy Florida? Where do you start if the pond is already slimy green? Thanks in advance!

  8. Coco says:

    Robert you rock! I’ve been holding down my own self-made small pond this spring/summer with no filters or pumps. Your blog has inspired me for new work to begin next spring ie the planting shelves/carpets.
    I love the quiet and stillness of the pond and sit by it regularly for meditation. Are your gardens open for visiting? I am also in SW Ontario 😊

    • My garden is private and not usually open for visitors. I do host gardening groups.

      • Denise Dodd says:

        Robert, perfect article.. I am in suburban Melbourne Australia.. we have a basic pond with goldfish, they get so big…. (even too big for the ducks as they do visit) and they breed away..therefore all must be happy.. maybe too happily breeding as our pond is now a light green and I cant see through it.. will plants be enough to clear it a bit.. we have pot plants on the bottom with plants.. just not sure we have the right ones?
        appreciate any suggestions.. Denise.

  9. Amanda J says:

    I want to start small with a middle sized fish pond. This was a super good read because I was just about to make a bunch of mistakes haha. Thanks for the super good comments too. I was wanting to keep tropical fish in the pond but heating it in the winter would be nearly impossible to do I guess.. sort of makes me sad but maybe I can find some cool cold water fish.

  10. Ian Sanders says:

    Complete novice here, now feel like I know a little something – which is a new concept. Many thanks for posting your (sorry, some of your) experience on here, it helps us a lot. Looking at creating a fish pond on a sloping garden with zero artificial involvement (electricity, fish food etc) and a glass viewing window. Why start easy?
    Thanks from Yorkshire, England.

  11. This was an awesome article – very helpful as we have just bought a house in the country with a naturalized, man made pond. Q: Will a dog swimming/going in and out of a man made pond create problems for the pond?

    • I doubt it. In the country all kinds of animals will use a natural pond and cause no problems.

      You do want to make sure you have a beach area where the dog can easily get out.

  12. Eric Liu says:

    Great Post. Thanks. Do you know how much water you lose from evaporation? In the summer, how much refilling do you need to do?

    • Lots of variables affect this. In my large pond, with normal rain fall, I only top it up once a season. This year has been a drought and I topped it up twice.

  13. Hi everyone. I read comments and it looks like a lot of people have gold fish. We have a broken swimming pool here and one of my flatmates put two gold fish there. Water levels are low. I saw one after 6 months his size doubled! Not sure what happened with the other one. Maybe died, maybe some of the birds cauth him (there are plenty of them here). The hole looks horrible and full of algea but fish can leave there and grow. Gold fish look like a really tough ones. But what about trout? I’m living in Australia atm and going back to Russia in Novemer. I want to find a land and build a pond and grow trouts there. I’ve read many resources and all of them say that you need running water, trouts don’t reproduce in ponds (only if you make it work like a hatchery but not a natural pond). Is that true? Does anyone have experience growing trout in a “natural man-made pond” ?

    • Trout need cold water. They do not breed in ponds. Most people who have trout buy baby trout and add them to the pond.

      My new book “Building Natural Ponds” includes a chapter on larger natural ponds suitable for trout and other game fish. Expected release in spring of 2017.

      • I did some reaserch and some people say that it is possible for trout to spawn in a pond if there is is shallow beds of gravel . And I’m really confused now. Maybe I should try to make a small experimental pond and put a few trouts and see how it goes? I know I can’t trsut anything I find in internet.

        • Matt says:

          Depends on species. Some species of trout absolutely do breed successfully in stillwater with the right conditions.

  14. Karen says:

    I had a hole dug..about 75′ x 23′ x 4-7′ deep and put in a liner two months ago. Because the hole diggers didn’t get it level the shelves are uneven with some deep and some shallow to totally exposed. I’ve started planting out the shelves with the only plant that can handle this heat, loose strife. It’s a beginning thing. A crazy storm added clay off of the hill which I am grateful for. I’ve added water lilies and, on impulse, 100 baby blue gill. Recently I added my two pet koi and a few of their babies. The heat out here is causing massive fish kills and I am fortunate to have lost only the catfish fingerlings and rosy minnows I bought from the fish truck. I’ve since added water fountains to mix things up and aerate. The water temperatures in the shallows are daily close to 90. My plan is to continue to add plants. I’ve got lots of frogs now and dragonflies too. It’s actually getting kind of loud out there now! It’s not safe to be in the sun too long at this time so it’s going slowly. My concern is that I may have inadvertently overstocked in regards to the bluegill. The fish truck lady told us a horrifying story about how they will get very big very quick and reproduce like rabbits!
    Here are my questions:
    1. Is the fish truck lady right and if so how do I reduce my bluegill population?
    2. After reading your article I am aware that I need more plants asap. This takes time. The one plant that I can get which I know will grow fast is anachris. My friend has it in her pond. It is invasive there. I clean out bushels of the stuff yearly from that pond. I dread adding the plant to my pond but if you think maybe I need to get a quick plant boost, I will do it.
    3. Thanks!

    • When conditions are right fish will breed. When they breed you may have the problem of too many fish which cause too much waste which results in algae growth. The only way to manually remove fish is to catch them.

      Anacharis is a floating plant. It will remove nutrients and help keep the pond clean. I prefer using rooted plants on the planting shelves.

    • Cheri Cottam says:

      Karen, i just saw this post, but if you still have the bluegill, let me tell you that they are some of the best eating fish you can have! a nice palm size fish will fillet nicely and make a wonderful meal. where we live, i find they seldom reproduce in water that doesn’t have an area that is shallow, say 6 to 8 inches deep. hope everything turns out well for you.

  15. Valerie says:

    I live in zone 4B in southern Ontario. Thank you for this article. Have you written a winterize your pond article. I would like to read how you do this. V

    • I have not – but will be writing several additional articles on ponds this fall.

      Winterizing is easy. On my large pond I add an aquarium air pump to keep the ice open so that the frogs have a better chance of surviving. On my waterfall I take the pump in the house. That is it.

  16. Beau Duman says:

    Great article, real glad we came across this. I have a pile of questions, hope you don’t mind. We are also in a zone 5 to 6 but not a lot of rain, 10 to 15 inches a year however the farmers are growing wheat, barley, canola, and such without irrigating. One of the goals for our pond is water storage to use for irrigating the gardens, so that I can manage the use of our well better, so in the 90 to 100 or so days of the growing season we will be pumping water out daily and topping off the pond strategically a few times a week with fresh well water. Do you foresee a problem with this?
    What do we need to help get the plants started? Would it help to bring home a couple buckets of creek or river water?
    Is there a proportion you would suggest for the area of shallow plant shelf vs. the deeper fish water?
    Thanks for sharing, I wish I could wait for your book, but I’m all fired up now to make this happen yet this summer.

    • Using the water for irrigation will be no problem.

      You don’t need anything to get the plants started. Bringing in water from a river might introduce diseases.

      I recommend 1/3 to 1/2 of the surface area be dedicated to plant shelves.

  17. Sindile says:

    This is a brilliant post! Thank you

  18. Debbie says:

    I just want to say how happy I am that someone else agrees with me about this subject! I have been saying for years that ponds are cheap to put in and cheap& easy to maintain without electricity! I use rinsed lava rock as a home for my bacteria, they love the nooks and crannies. And lots and lots of bare rooted plants. That’s all it takes!
    However I must admit that I love spitters, so I always add a couple and make sure their output is flowing over pea gravel, lava rock, or plant roots. One or two of these totally clears up the green, but then yeah, you can see the bottom liner.
    One trick I enjoy for covering the water surface is to use Impatiens. I rinse off the dirt (of course) then poke the roots through a foam meat tray. It will float and the flowers will quickly spread to hide the tray. You could anchor the trays, or let the breeze move them around.
    Again, so glad to see this post. Keep spreading the word!

    • Julia Bunn says:

      Brilliant! Thank you for the idea of the meat tray! I have been puzzling about how to float my pitcher plant without it looking doofy.

    • shantam says:

      what are “spittters” mentioned in a comment?

      • Debbie Kays says:

        Spitters are statues that have water routed through them, so it looks as if they are spitting the water out. They come in all sizes, frogs, turtles, angels, herons, all kinds of things. They will have a place to attach a hose from your pump on its back or bottom side. The water then flows out the figure’s (usually) mouth.
        It’s not that forceful, but any water flowing over any bare roots is beneficial to the pond. And it gives that wonderful sound of moving water!

    • Trose says:

      Thanks for this unique bit very useful idea using the meat foam trays. I live in southern USA, zone 8. My tiny koi/goldfish pond needs plants lots of plants but I have no plant shelves. I’m hoping this idea will work in interjectingreat plants into my pond which normally would need shelves.

    • Mary Ann says:

      Wow! Great idea with the foam meat tray. Have you tried this with any “pond” plants? My pond is in shade under lots of trees.

  19. Gerry Lockwood says:

    I left a question 6/28/16 and there has been no response. Just checking to see that I sent and responded correctly because it still says “Your comment is awaiting moderation. ”
    Thanks. Hope to start on the pond soon.

  20. Shawn says:

    Two years ago when I was deciding whether or not to bring back to life an empty concrete pond in the backyard of the house where I now live in Las Vegas, I came across your site. Although all the stores Out Here Sell filters and big pumps, I decided to do my best just to let my pond create itself naturally following your guidelines. Now in its third year, the pond is doing great. I have a couple small pumps in there just to splash water around for my amusement. The Goldfish seem to like 2 sit in the flow of water. But other than that, the pond has just been going on its own. All my plants came back from last year. My cat tails are spreading. It’s really a gorgeous and relaxing addition to my yard. By the way, it’s about 20 feet across and only about 8 to 10 inches deep.

  21. Ron D says:

    Fascinating write-up! I’ve been considering digging a few mini-ponds in my yard for years. Two questions:

    1. I’m in southern California; our average summer highs are in the mid-80s Fahrenheit, but mid- to high-nineties are not rare (heat wave two weeks ago reached 107!). I’m not sure what your max temperatures are in Ontario, but how do you suppose higher temperatures would affect the results you’ve seen?

    2. I don’t have a lot of space in my yard, so my ponds would be fairly small. Have you experimented with smaller ponds; and if so, what do you suppose a minimum size is to support a functioning ecosystem (that can keep the water clean without filters, etc.) would be?

    • Higher temps won’t change things except more evaporation.

      I have not worked with very small ponds, but they would be more difficult to keep in balance.

    • Debbie says:

      I have had several small ponds and have found that it needed a little help. If you add water flowing over your bare rooted plants, you’ve just made a fabulous filter! I’m always on the lookout for cheap small pumps, often I find table top fountains that are crackled and discounted. But the little pump still works and works well in the pond.
      Some great plants for this are mini cattails,water hyacinth, and various rushes. They are heavy feeders and will help keep pa pond clear.
      The temp will increase your algae load as well, keeping a lot of the surface covered with plants/lily leaves/etc. really helps. Water hyacinth really loves the heat.

  22. So happy to find your post Robert! We followed your suggestions. Put in our 8 x 15, 3 foot deep lined pond with plant shelf, lined with stones and marginal plants. The marginal plants are anchored in the stones without soil. They’re alive but not growing much. Two water lilies in soil are growing very well. Water hyacinths slowly coming along, but duckweed very slow to grow. Pond is 8 weeks old. Is there simply not enough nutrients yet for the plants? The water was cloudy in the beginning, but crystal clear for 5 weeks. We added five small goldfish 5 days ago. They look very happy and eating from the liner. Will the fish be adding nutrients for the plants now? Do we risk starving the plants and/or the fish? Hope we’re doing this right – we’re having a blast!

    • Fish poop will feed the plants. No worry about starving fish or plants. Just give it time.

    • Debbie Kays says:

      As Robert says, it takes time. Plants will take a season or maybe even 2 before they get larger, just as in planting perrennials in your land garden.

      Are they getting a good amount of sunlight? If it’s shady, they’ll take longer to grow, but they will grow.

      Also be sure they are planted at the appropriate depth. Many marginals only like a little water on their feet, others prefer to be submerged. If the shelves are too low for some of your plants, try potting those plants in a pot (like the cheap plastic ones they come in) but don’t use soil! Use some pea gravel to pot it. Then prop that potted plant up on a brick or rock to the appropriate height.

      That said, adding bricks to the pond, or concrete blocks, will alter the water’s pH. If that’s a worry to you, avoid them. I used both many times and my solution to the pH issue was simple. I threw away my pH tester!! I stopped testing my water and never did a thing to correct it, and just let nature take its course. And never had any issues that I could tell. My fish and my plants grew and grew and grew!

  23. Gerry Lockwood says:

    I read your article on DIY natural ponds in the Oct/Nov 2015 Mother Earth News. I am thrilled to switch my tiny store-bought pond, which can not stay clean even with a pump, into one that will be self-sustaining.
    One question after looking at rocks at the stone store: which rocks are best for plant shelf areas – smooth, like river stones or porous, like lava rock?

    • The goal is to have as much surface area as possible for bacteria to grow on. Lava would be better than smooth for this. Small is better than large. Cheep is better than expensive.

    • Sisha says:

      Careful with lava rock, it’s extremely abrasive to your liner so if you do use it don’t put it under any pressure like walking on it, you are better off with small pebbles for planting.

  24. Stephanie says:

    First, thank you for sharing your experience! I’m so relieved to read about your success with pond without filter because I’m hoping to do the same. I have a 100 gallon stock tank with 2 small goldfish, 2 small koi and 5 minnows. The plants were growing slowly until I added the koi fish. I thought of cleaning the bottom of the pond but the bottom is covered with mulm (I just learned this word!) and roots from the lily plant I’ve had for 10 years. To clean it means pulling out a whole sheet of roots. Should I leave it alone? I don’t want to touch it. All the fish are happily swimming around, even rooting the bottom. Water is a little bit green but I just added some more plants and hope it will clear up in time. I don’t know if the pond will accommodate the growing fish without filter but I’m hoping it will. To be honest, I’m scared because every store I went to told me otherwise. By the way, the pond went through 2 years with just a handful of minnows and I’ve only added the other fish 2 months ago. I’d appreciate any advice. Thank you!

    • You probably have too much fish for 100 gal – maybe not today, but fish grow. For large koi it is recommended to have 100 gal per fish.

      I would not clean out the bottom. Microbes live there. If you start getting a lot of stuff at the bottom, it does not hurt to fish some out from time to time, but don’t clean the bottom.

      I don’t blame you for being concerned. Why believe me when all of the stores and other web sites tell you you need pumps and chemicals. I was in the same boat 8 years ago, but I did not have even one person say it would work.

      I will be publishing a book in spring about creating natural ponds following the ideas I have presented in this post.

      • Debbie Kays says:

        And why do you think all the stor es and magazines tell you to use pumps, filters, UV lights and chemicals? The pond business is a booming one, and if they tell you to go natural, they won’t make money. Their object is to sell.

        • That is certainly true. A lot of this is also in response to koi people. They like lots of large fish in a pond, and when you do that it is much harder to go natural.

          This is really no different than other forms of gardening – most of the stuff being sold is not needed.

  25. Air pumps are sometimes used to move a little water in small ponds.There are several articles online that you can read .Research the subject.I once had an indoor natural aquarium and used weeping willow branches to get rid of the green algae.The fish took care of the plants and the plants cleaned the water.Perhaps you can plant a small willow at the very edge of your pond .Willows will grow in standing water.(Get a small species)

    • Air pumps are used in large ponds and they seem to reduce algae. Or make the pond with plants and you don’t need the air pump!

      I doubt willow will reduce algae – but if you have a scientific reference to show this works I’d love to review it.

      • Kent Freeman says:

        Hello. I’ve had a 100’x30′ pond, up to 10′ deep which I had made while leveling out a place to build my barn. It’s fed by run-off from the hill out back. I was wanting to aerate the pond because I thought it would make it clearer and look nicer. After reading your article and many of the comments, it seems I’ve been real lucky.
        I’m in southern Ohio. My pond was dug out, earth pushed into place for a dam and a low area for over flow. That’s it. I have a lot of frogs! Some fish were thrown in from time to time, but no one has caught any for years. I do have three large turtles, about 12 to 15 inches in diameter that have hit a fisherman’s line. Right now I have quite a bit of algae. It doesn’t smell at all. There’s plant life in and around it.
        I want to add a waterfall from up the hill which would be about 60′ away and I’m thinking 20′ up. Line it with washed gravel about 3/4″ to 4″ in size. I’m thinking that will clear up the water somewhat. What do you think?
        Later this year or next, I’m planning a greenhouse and did some research and would like to try to have the pond fertilize the plants while also adding a editable fish. Any advice? Anyone?

        • The waterfall will aerate the water which is good for animals and plants. The rocks in the waterfall and river leading to the pond will get covered with bacteria and they will help remove nutrients from the water – that is good. I doubt it will be enough to remove the algae from such a big pond, but it will help.

          Pond water would be excellent for watering plants. By removing the water containing nutrients resulting from decay, and replacing it with fresh water you should also reduce the algae.

      • Alex says:

        Hey i read the comments down to june 13. Is the book out yet and whats the full title? Did you ever get to those articles on winterizing? You asked another poster to refrence research data, do you have a collection of such things, would you mind sending it my way or making it accessible? I have no interest in the cancer that is facebook, is there any other way to access the information there as i will not use the web page. The main problem it seems you suggested from this artical is build up from debree in the bottom of the pond, i am assuming the hypothesis is over time the pond will fill in, was a solution ever found?

        Good luck to all of you. Have wonderful lives.

    • shantam says:

      no mention is made whether new water is flowing in and out of your pond… it seems if you do not recycle new water, the whole pond will get rancid and fish die and everything get bad.. or am i missing something ?? thanks!

      • Diana R. says:

        Hi Shantum,
        Our pond has no groundwater source and it’s doing very well, supporting frogs, fish, turtle, snails, toads, microfauna, etc. Most of the time, ordinary rain is sufficient to refresh the volume. Occasionally, we add a few gallons of well water through our hose. As Robert emphasizes, plants are the critical element of man-made pond health.

        • Debbie Kays says:

          Shantam, in a well balanced pond, with lots of bare rooted plants, and rocks/stones for algae to grow on, there is no need to recycle the water. The pond will clean up its water by itself. Microbes will flourish and consume the fish and plant waste, producing nutrients for the plants to consume and grow, and on and on. I don’t know the science of it, but I do know that it works!
          If you scoop up the muck from the pond bottom, it will stink like nobody’s business! However that is exactly how it’s supposed to smell. And so long as you leave it alone on the bottom, you’ll never even get a whiff of it.
          Plants, plants, plants!! (and no soil!)

          • James A Creech says:

            We are nearing the completion of our pond and have always planned to go natural with no artificial filtration. Yours and Robert’s comment about stirring up bottom much makes me wonder, though, will a waterfall with pump to run it stir things up such as to create problems with smells and high turbidity? This question undoubtedly shows my experience, not having yet engaged my pump! Thanks, all!

          • Material will settle away from the waterfall and pump, therefore running the pump does not cause a problem.

  26. theo says:

    Hallo from Brussels.
    I have a pond (5m/5m/1,5m) with KOI in my garden (in the middle of the city) with filter and pump. It came with the house when I bought it. I never had any experience with ponds or fish. They are doing well (10 years)
    However, I love your approach and want to try it. First adding lots of plants and then gradually diminishing the pumping and filtring.
    The bottom slopes from a depth of 5 cm to 1,5m. There is ample room, rocks and pebbles to have many more plants than I do.
    Two questions:
    1. can’t you really tell something more about the kinds of plants that are most efficient for nitrates etc…. I understand it depends on the climate, but not even something about the genera?
    2: my KOI eat the waterlilies. alternative to provide shade in summer?

    With kind regards

    • I really don’t know which plants use more nitrogen, but probably the ones that grow the most leaf material will use the most nitrogen. Use plants that other local ponders use. I use iris, cattails, waterlilies and marsh marigolds a lot – but they grow easy here. I am also in zone 5 and want things that survive the winter. I am sure Brussels is a bit warmer so you have more choices.

      Koi and plants don’t get along very well – the fish eat and disturb the plants. You might have to keep the plants and fish separated. I don’t have an alternative solution to waterlilies since koi will eat most floating plants.

      • Dave Crosby says:

        How about using some type of plastic fencing in the water to separate the lilies from the fish? The plastic won’t rust, a neutral-colored plastic will be hard to see, and if the mesh is small enough, it might keep the fish from getting to the lilies. I don’t know if this will work (especially in a 5mx5m pond), but it might be worth a try. The mesh could be weighted at the bottom, suspended (from a float?) at the top, and possibly anchored to the sides of the pond (to create a “fish-free zone). Just a thought….

    • Debbie Kays says:

      Mini-cattails, water hyacynth, water iris and various rushes are great for cleaning up a pond! I love blue rush and corkscrew rush myself.
      One possible method of keeping your koi away from the lilies, is to make a floating net island. Get a hula hoop, hang a length of black tulle around it, making sure it’s long enough to reach the bottom of your lily pot. Place the pot inside the hoop/net contraption and let the hoop float above. Just be sure to check daily, to be sure no fish jumped the hoop, and needs to be rescued!
      Also, a good idea for providing shade is to make impatiens islands. The impatiens flower loves the water. Take a few plants, rinse off the dirt from the roots, then poke the roots through a clean foam meat tray. Float this in the water. The flowers quickly fan out to cover the tray. It provides shade as well as more roots to clean up your water! Plus they are very pretty floating around!

  27. I built a outdoor classroom frog pond with my students. I added goldfish just incase the frogs didn’t show up. I am SO amazed at how well this pond is doing! It is a self sustaining habitat for goldfish, tadpoles, frogs, snails, and other insect. I have taken a sample of the water and pondlife to keep in the classroom and even in the small tank it just sustains itself. Everyday I am amazed at how well this pond is doing. Manmade, liner, no pump!! Thank you for your blog. It explained so much! We clearly did just what we needed to to make out pond work!!!

  28. Jamie says:

    My county is forcing us to aerate the water because there is an ordinance against “stagnant water” because it’s a “breeding ground for mosquitoes”. When our pond was first built, there was a slight increase in the mosquito population (you could barely tell since the mosquitoes are so bad here!) until the frogs moved in and started breeding like crazy. It has been a little over a year and we’re still dealing with algae (single cell) while we wait for the plants to grow in more. We have a lovely ecosystem with fish, frogs, dragonflies, minimal mosquitoes, and no smell, but we’re going to get a fine anyway unless we put in a pump.

    Mostly I wanted to complain (heh), but I also would like to know if you have recommendations for a pump to appease the code enforcement officer that won’t be difficult to install in an already established pond and won’t damage the ecosystem, if such a thing exists. Our pond is about 5 feet deep and 15 ft diameter. Thank you for any help!

    • Never heard of such an ordinance. Do you have to aerate natural ponds too? Clearly a case of government officials not knowing anything about ponds.

      The easiest way to aerate a pond is to add an air pump used by aquarium people. I don’t know if that meets the government requirements.

      • helen says:

        I have a 1 1/2 acre pond in my back yard in Hendersonville Tn ..I never have had a problem with mosquitoes. I think the bass and brim eat them . It has a good year round spring feeding it. I am getting older and having a harder time maintaining such a large pond. The thought of selling come to mind time to to time. It is beautiful most of the time but does have the yearly spring turnover. Shoud I just let the algae stay on the pond and let nature take care of it or do you keep on treating the water and using fountains .

        • You can let the algae grow, or add a fountain will will help a bit to cut down on algae. Add more water lilies – they reduce light getting to the algae and it will grow less.

    • Debbie Kays says:

      Does the county give guidelines as to the required pump’s size?
      If not, grab a $25 pump and some tubing. Sit the pump on the bottom, and you have a few options. Make it as a fountain and let it spray up. Or attach a cute spitter and have it spray into the pond. Or make a little waterfall area by covering a small area with plastic, top with stones and situate the tubing so that the water returns to the pool. Even if it’s just a teeny falls, the goldfish will love it! They’ll swim under it, get pushed down, circle around a go again. It’s like a fish roller coaster!
      An added bonus to any of the options is that you will be adding the sound of water.

      • Julia Bunn says:

        Be careful, though. Our fish liked to jump up into the waterfall, like spawning salmon. A few landed on the ground beside the pond and perished before we saw them and could rescue them. We disassembled our waterfall, and have decided to wait to reconstruct it until we can make it so the waterfall is further over the pond’s edge. That way, when the fish jump up into the falling water, they will fall back into the pond, and not onto the ground.

        • Cheri Cottam says:

          Julia Bunn, aren’t goldfish so entertaining? we had a hose flowing water into an upper pond, maybe 1 and 1/2 inch in diameter, and one of our goldfish kept trying to swim up the water flowing out of the hose into the hose itself. too funny!

  29. I am building a 24×19 pond that will be about 4 feet deep in the middle. We were planning on digging a smaller 6×3 pond above it that would at most be 12 inches deep and having that cascade into the larger pond. Would that be suggested? If so what pump would you recommend?

    • Sounds good. Select the pump to meet your flow rate requirements. There are two variables; height and flow rate – which are connected. Height reduces flow rate, mostly due to friction. use large tubing and you reduce friction. On my large waterfall – 12 feet high I use a 4″ PVC pipe and loose almost no flow. The size of the spillway is also important. Double the width of the spillway, and you need double the flow rate. I suggest googling several sites for pump selection – it gets a bit too complicated for here. But I prefer an external pump.

  30. Jay says:


    Thank you for the valuable information. I am planning to build a raised pond with bricks and a glass window to view the fish. The pond will be 3m x 1.5m and 1m deep.To keep it a natural pond what am I supposed to use instead of the pond liner. Am a newbie so am sorry if this sounds stupid. Also I have been reading about fibreglass pond, whats your opinion. Thanks in advance

    • use the liner or a preformed fiberglass pond – both can be made to look natural. The key is to hide the liner with stones and planting shelves. With planting shelves all the way around you don’t see the liner except in deep spots and that will soon be covered with microbe slime. Some preformed ones do not have enough planting shelves to allow you to hide it.

  31. Tony Penson says:

    This is a great idea. I am now inspired to install my small pre-formed pond. I don’t have any power at the top of my garden and don’t want to go through the performance and expense of the installation and required certification by UK law with any electrical work. I will keep up with the posts. Thanks Tony.

  32. Pamela Smallwood says:

    Great info on ponds! How much shade does a pond need? I have a wide open spot where I could pur a pond but it would get full Texas sun. Also interested in your opinion of a container pond in case I have to go that route- in which case it could be in shade.

  33. Laurie says:

    Great article. I have a small frog pond in the backyard without filtration. It is 1.2 m x 600×400. I have had it for 3 years without any major issues. By mimicking nature I found that plants and substrate alone can do the job. I will use some of your suggestions when replanting next season. Thanks.

  34. Sandy says:

    Fantastic post, I’ve been referring back to it as I’m constructing a small pond (5’x10′) and am hopeful that it should work on this scale as well. I’m calling it my ‘experimental’ pond and if it works out then I hope to enlarge.To the side and separated by a rock topped berm is going to be a bog garden, which was my original motivation, but once I started digging I figured “why not just keep going?” It’s also in a pretty shaded part of the garden so I’m hoping this might help control the algae as well. We’re tucking a small grotto beneath a huge rock that we excavated while digging and I’m hoping to get some moss growing there. I’m curious to how beneficial that would be.

    • How beneficial will the moss be? It looks nice and will probably grow well with the extra humidity of the pond, but it won’t do much to keep the pond clean. the shade will keep algae down but if there is too much it might also be difficult to grow plants. some like water lilies will grow, but may not flower much.

      • Sandy says:

        Thanks! The pond gets a little sun, here and there, but I’m not too concerned with flowering, as they’re pretty short lived anyhow. I like moss in general, so in places not suitable for regular plants I think I’ll introduce it..

  35. Steve says:

    I live in Vancouver, how deep does a pond need to be to avoid freezing solid? I was thinking of digging an 8’x5′ pond.

    • I am in zone 5, and I doubt mine ever freezes much past 1 foot – my deep one of 4 feet deep. In Vancouver, I doubt you would reach 1 ft.

    • Carina says:

      Hi Steve, I’m also in zone 5 and last year enlarged my tiny pond to about 8×4′. The deep end is a “well” almost four feet deep and my goldfish survived under the ice and the lily plant looks pretty good now that it’s warming up. If you don’t plan to have fish in there, I don’t think it matters if it freezes solid.

      When my pond was smaller, I brought the fish inside for winter. My oldest fish is 8 years old and still trucking!

  36. doggy20 says:

    what type of plants can I use in my pond?

    • Any water plant that is suitable for your climate. Google for “water plants for ponds” and you will get some good lists.

    • Debbie Kays says:

      Don’t forget to check out your garden store for land plants that like water. Sometimes you’ll find the same plants marketed for both land and pond, and guess which one costs a lot more?? Houttuynia (chameleon plant) is one example. I’ve seen it in both places, and the pond section sells it for a lot more.
      Just remember to shake and rinse off all the soil from a garden plant before adding it.

      Other land plants that grow well in the water are spearmint (and probably other mints as well), lemon balm, and creeping Jenny (or golden Jenny). They are invasive, so if you want a nice tight little bundle of plant that stays right where you put it, these aren’t for you!

      • The advice is good except you have to make sure these plants do not escape into the garden. It took me 3 years to get rid of Houttuynia (chameleon plant) from the garden – came as a weed from a friend. Still trying to get rid of mint after years. I would never put creeping jenny in my garden.

        All of these will grow well in a pond.

  37. Gayle Clemens says:

    can you swim in these ponds? How small can you go and keep the balance? Is it harder in a big pond or easier to keep it healthy?

    • You can swim in them. In fact natural pools are becoming popular in Europe. I don’t know how small you can go, but it is certainly easier to keep in balance in a larger pond.

  38. Dustin Spero says:

    Hi Robert,

    Great post! I purchased a house with a 100×50′ kidney shaped pond that is lined on the property. There are decorative rocks around the edge but nothing in the pond and most of the sides have a good slope to them. Any ideas on how I could add plants to help clear up the water? I thought about nets on the side with rocks?? Before I found this post, I had added a aerator to the deep end which is about 6′. The pond slopes from shallow to deep. There is also a fountain in the pond. I had a lot of algae last summer due to lawn fertilizer making its way in. I really want to have clear water to allow the family to swim. It’s a shame to have such a large pond and not be able to swim. Any ideas from you or your readers would be greatly appreciated. Thanks again for the great post!

    • With out planting shelves it is difficult to add enough plants to keep the pond clear of algae. Since the pond is built it may be best to look at mechanical filters to do the job. An alternative is to add a second pond beside the first, and use if for filtering the water. the second would be shallow and full of plants. Water would be pumped to the second pond, and allowed to flow back to the main one.

      • Debbie Kays says:

        I haven’t used many shelves in my ponds. (Although I know I should!) Instead I kinda build my own, by placing a big flat rock on top of other rocks, making a kind of table. The plants sit on the table, and the fish have a fun cave underneath!
        And I have to say, you should work on preventing any runoff from your yard, from entering the pond. Try building up a berm around the edge.
        And I must add that I’ve always dreamed of having a bog filter like you described there.Bogs are cool.

      • Donna says:

        I bought floating plants for aquariums which do not require anchoring and they propogated so well I’ve had to remove some! You can try those if you do not have planting shelves. Worked great for me.

  39. Kate says:

    Hi Robert,
    I’d like to know if you think a cement pond is as good as a pond with a plastic liner.

    • Not in cold climates. If you have frost, cement will eventually crack. In warm climates it will probably work just as well. A newly made pond could be quite alkaline and you might need to replace the water a few times to reduce the pH.

  40. David says:

    I have 3 natural ponds and all run excellent, i have the perfect balance as you explain. Resulting in frogs white clouds and goldfish regularly breeding, however i had mosquito fish and they were awful fish. Not worthy of any water, to the point where a few were chucked into my aquarium gunk tub used strictly as high potent liquid fertiliser. They live in it to this day, well at least the smallest one was last seen !!

  41. Jennifer simmobds says:

    This is wonderful but p,ease someone tell me, do I need to change my pool liner or can I just throw in dirt and rocks around it? I would like an aesthetic waterfall but loathe to spend money on filtration and aeration. Am I ok to do this? Aussie here. Pool killing me to mai Tain. Kid wants turtles so…….

    • I am not sure what your question is. If you are thinking of getting rid of the pond and filling it with soil, I would remove the liner.

      • Jen says:

        Yes sorry, iPad typing. I wanted to know if I could retain the pool liner for the pond and if filtration or anything electrical is absolutely not required unless I wanted a waterfall.

        • I am not familiar with pool liners, but I suspect they are thinner than pond liners, and as such might not last as long. On the other hand, pool liners have a back support to protect them. You can certainly use them provided they hold water. everything else I write about should apply to a pond build in an old pool. adding planting shelves might be a problem.

  42. Dave Crosby says:

    Your article confirms my initial thoughts RE: pond construction. Around 2001, I installed a pond at our hiking club’s remote cabin (no electricity, no running water) in SE Pa. near the Appalachian Trail. While I did have a solar-powered pump (a PV-direct system), I also used the shallow end of the pond as a plant-and-stone-filled “filter”. After several years, the pond approached “eco-system stability”, but the liner was damaged by a bear looking for a frog dinner! We patched the liner, but the bear came back, this time slashing the PVC liner beyond repair. This coming year, I will replace the liner with an EPDM rubber one. But what else can I do to mitigate any on-going bear damage??

  43. Diana R. says:

    Well, we survived the summer, but on Dec 24 (in the upper 60s in Pennsylvania!) we are experiencing the worst algae bloom since we installed the pond. I got alarmed when I saw the fish at the top of the very cloudy water, evidently seeking oxygen (just like you said. Robert). We scooped out a fair amount of algae and decaying leaves and set a sprinkler on an exposed rock to aerate the water. I haven’t seen the fish again and the water looks somewhat less cloudy. Any other things we should do? Thanks and merry Christmas!

    • The fish were indeed gulping air to get oxygen. Better than a sprinkler are air bubbles. You can use an aquarium pump for them. The air bubbles will also tend to keep the pond from getting a solid covering of ice. Once the ice is solid there is no gas exchange and CO2 builds up.

      The warm temperatures probably increased the decomposition of the leaves, and the normal pond plants are already dormant. Nutrients being produced with nothing to use them up except algae.

      • Diana R. says:

        Thanks very much. Do we need to meet a certain gph or other criteria for the pump to be effective? Our pond is (very roughly) 3500 gallons.

        • You use the air pump to just keep a small hole in the ice so it does not need to be a big pump. The amount of air needed depends on how cold it gets and how long the cold lasts. I don’t have any recommendation on size.

      • cody fox says:

        I am planning on digging a rather large pond for fish and swilling. Just need to decide bass and blue gill or kio, always wanted kio. But would me swimming in it stir up the dead matter at the bottom?

  44. Oraine Nelson says:

    I like your post and recommendations. I notice in the past, especially in around the 18th century, ponds existed that were created without pumps or filters and they still had fish in them that were able to survive. I also notice that these ponds had water plants, as you said, like lilies or lotus.

    I would like to create such a pond where I live but I believe I need additional guidance especially as to how to ensure the pond’s water level remains as constant as possible. Any suggestions.

    • Natural ponds don’t maintain a constant level and it is not needed for pond health.

      To keep a constant level you have two problems; too much water and too little water.

      If too little, all you can do is add more.

      You need to design for too much. I always include an area where the edge of the pond is lower than any other point. that way when it rains too much, I know where the excess will flow. I make sure it flows away from the pond – you don’t want it flowing under the liner.

  45. Sue says:

    Loved the article. I have a 100 gallons preformed pond. And have it all winterized and ready to go with a heater in it. I leave two pumps running but not sure if I should take the filters out and just leave the pumps running. I live near Chicago, Illinois and winters are brutal. The ice in my pond never completely freezes over, but it is harder getting the filters out every couple of weeks to clean them, especially since I am getting up in age. Can I just leave the pumps running to circulate the water for the fish, or do you suggest keeping the filters in there too?

  46. Molly says:

    I was so excited to find this post and this blog, and to hear that others in even less tropical environments than my zone 6 Ozarks have successfully created natural backyard ponds.
    My 15x30ish concrete swimming pool has been home to a thriving population of goldfish and a handful of pond plants for several years with no intervention of any sort. The population of fish has grown, it has resident frogs and even at least one young pond turtle. It also attracts many dragonflies. I would like to make it more accommodating to the needs of the birds and small mammals, as it currently is still steep sided with only floating logs and milk-crates for self-rescue, but no easy way for animals to approach safely to drink. Because the bottom slopes toward a small deep area in the middle, I can’t just dump in rock and dirt to create sloping sides, and I don’t want to lose the depth in the middle because I want to be certain all the residents have a place to retreat to in the coldest part of winter. I am on a ‘no-budget’ budget, but imagined perhaps tipping in wheelbarrow loads of large hunks of broken concrete and broken concrete blocks that would slide to the bottom, creating something against which future wheelbarrow loads of debris could rest against, then I could add soil and give it time to settle then see what I’ve got before adding more material around the edges in hopes that it would pile up creating the sloped sides in time. I would love to hear other ideas and suggestions for how I might accomplish all this, since I have all winter ahead of me to accumulate materials in anticipation of improving the pond habitat in the spring once everything has come out of winter hibernation.

    • I would not fill the center in case you decide you want it open in the future, Why not just make a raised corner using stacked cement bricks. You don’t need a big beach for animals.

      • Molly says:

        Found this site again! Yes, Robert I think that’s a better idea. The more I read the more I see that my original plan had a lot of flaws. The shallower end of the pond is flat and lends itself to stacking cement blocks, and while it’s only about 1/3 the surface area of the pond overall, I think if I get the right plants growing there it will filter the water enough to even use the other 2/3 of the pond as a swimming hole.

  47. Rick Acker says:

    Hi Robert! Love the article. I have a small 10 by 10 pond that I raise waterfowl on. (3 feet deep in the middle) I have a drain in the middle and I’ve been just pulling the plug every week or so to clean the water. I’ve often wondered if I let it go natural if it would work with waterfowl and all their poop. What do you think? Thanks

  48. Carol says:

    BTW I am from the UK

  49. Carol says:

    I love your pond and your very helpful post 🙂 and wonder if you would advice me:

    I have a teeny 11gallon preformed pond (few weeks old) which I hope to attract wildlife, frogs etc to get rid of slugs and snails. I have bought a basket of marginal plants which sit nicely on the larger shelf but the slugs /snails (I think) have immediately started to devour the leaves totally leaving only the stem on one of them, as they were expensive it has put me off buying more do you suggest anything?

    I also see what looks like long trails of green excrement on the white rocks I have under the surface and wonder what is making it? TIA

    • Try to buy plants that are plentiful in your local ponds – not exotic plants. If they survive locally there is a better chance the local population of slugs will leave them alone.

      I suspect that the green excrement is from frogs or toads. This video might help

      • Carol says:

        Hi Robert

        Thank you for taking the time to reply and so quickly 🙂 great advice about the slugs thanks, the plants are local plants bought from my local garden centre.

        I am surprised and excited to think that frogs or toads may already have found my tiny pond (2-3 weeks) so thanks for the (cough) interesting video, they sure make a mess but the trails I am seeing are much narrower??

        After seeing the video I am now wondering how difficult will it be for me to keep the correct water balance; I don’t want crystal clear water as I want it to look natural, but also would prefer not to if possible, see lots of trails covering the stones which are right at the front of the pond (viewing point), placed to act as a sloping area do I need to remove the excrement to avoid it overtaking the pond or is it good for the pond? TIA

        • What ever kind of excrement it is, it does contain nutrients. Too many nutrients in the water and algae will start to grow. How much is too much – hard to say. It depends on the amount of water and the amount of plants.

  50. Elayne says:

    Thank you so much for your informative post. For about a year now, I’ve been planning a two-section pond with a connecting “brook” and a waterfall. I’ve done a lot of research and love the information you give about doing it naturally – without the use of electronic equipment. My question is can I still have the waterfall without a pump? If not, what will I need to have?

    • Maybe I don’t understand the question, but water does not run up hill on it’s own. A pump is needed to move the water to a higher level so it will flow down, causing the waterfall. There are many types and sizes of pumps and picking the right size is not easy – boy – that is a helpful statement 🙂

      If you are just starting out with waterfalls, and the system is fairly small (preformed ponds usually are) then I would get a submersible pump. They take a bit more work to keep them clean, but they are easier to install, and they usually cost less than an external pump.

      The key to pump size is to use the largest hose possible from the pump to the top. A large hose means less friction, and more water being moved. In turn this means you can use a smaller pump. I suggest you to talk a store selling ponds and ask them to size the pump for you. You will need to give them the size and height of your system. They will probably try to sell you a small hose – insist on a larger one. Many pond ‘experts’ don’t understand the importance of this.

      My main water fall pumps water to a height of over 10 feet and a distance of 40 feet. I see very little loss in flow because the hose going up the hill is a 4 inch diameter pipe that is very straight – very little friction = maximum flow.

  51. Riva Gustafson says:

    hi Robert, in researching for my turtle pond you’ve helped a lot, here’s some cool links for liner less ponds, and
    the only thing i worry about with this, is if you’re in an area that freezes your fish and turtles will need to hibernate. they go to the pond sludge to stay warmer, and say hidden from predators. anaerobic bacteria produces more “dangerous” chemicals than aerobic, so your fish might have more problems. granted, most koi ponds and such are seriously overstocked compared to natural/wild ponds, so that’s gotta be part of the problem. if you have a source for it, adding pool filter sand(high grade quartz sand, nontoxic) provides a beautiful, cheap, consistent substrate for plants and particularly bacteria to grow in, but i’m betting that’d only work with a lined pond, otherwise the sand would probably add too much drainage to the soil underneath. if you wanna know whether you need a liner for your pond, dig a hole next to where you want your pond, and dig it as deep as your pond will go. fill it with water. see how long it takes to drain. if it’s less than a week, you’ll need some serious amendments to your soil, or a liner. less than a month, some ammendments, but not much. a month or more, you can probably get away with not amending your soil, but i’d say add bentonite clay, or use the gley method linked to above to get some good stuff. duck poop will help seal in linerless ponds over time. and duck poop a lot.

    • Fish, turtles, and fogs do hibernate in the bottom, where the CO2 levels are highest. If a lined pond freezes over, for a long period they will die.

      A linerless pond will always loose some water. It becomes a function of how fast it looses water, and how much you will tolerate. Bentonite does work.

  52. Hi Robert. This is great advice – exactly the kind of thing I am looking for. I care for a flock of chickens and outside their coop is a large concrete depression that I really hope to make into a (low-maintenance) pond. I would love your plant recommendations, besides irises. Also, any advice on how to make the planting shelf when the sides are sloped? Should I still use a plastic liner and the carpet material for the shelf? Thanks so much!

    • As far as plants go, use local plants where you live. They obviously like your climate.

      Once you have sloped sides, it is not really feasible to make planting shelves. You can however, uses pots right in the water, either sitting on the bottom or raised up with some rot-proof material.

    • devery2014 says:

      Devery Wallace
      I have a pond that is built on my deck it is a box and with plastic lining structure using a pump that sends water up to a fountain . There is no ledge to put plants and rocks. We have some plants, adopted snails and lots of algae. Can you make suggestions to help minimize the algae that is in the pond as well as hanging from the fountain.

  53. nancyleep says:

    Dear Robert – thanks for much for this article. We rent a lovely little home with a fairly large (large for this small backyard) pond (approx 8-9 feet in diameter – although not a circle – and 5-6 feet deep) with a creek-like waterfall feature. Because the pond does NOT lose water when the filter is off and the creek isn’t running, we suspect there is a leak in the underground piping (loses lots of water when the creek is running). The liner has been repaired and I’ve been looking for a way to keep the pond lovely without the creek running. Your article and the responses to it have helped me understand a different way to keep the pond beautiful. So next year we’ll try a “dry creek bed” and a pond with some floating islands.

  54. Melanie says:

    Could you advise me please? Can I apply the same guidelines for a natural pond to very small ponds? Thanks

    • Probably.The problem with small ponds is that there is less room for error. But most of the principals I discuss apply.

    • Diana Restifo says:

      Hi Robert,
      Our one-month old 19 x 12 foot pond is undergoing an algae bloom, I think, in the form of a soft brown mat on all surfaces that is now also clouding the water. Tiny fragments (perhaps dead?) are floating on the surface. It’s been hot here, so it’s not surprising. What affect might this have on the five small bluegill sunfish in the pond? We also have frogs and snails. We are slowly adding plants, but we need many more- it will take some time. We don’t mind algae but would like the water to support other life forms as well! Thanks for your expertise.

      • Pond life will be fine. If a lot of algae is dying, it will reduce oxygen levels in the water which is not good for fish. If you see them with their mouths at the surface of the water – they need more oxygen. then you might remove some of the dead algae.

        Until you get more plants you can always remove some algae. But it is probably not necessary.

  55. Peter says:

    Just my bit for the topic: I have a pond with pump installed. I bought a pump and filter including UV lamp for sole purpose to solve green water algae. It did work, but UV bulbs need rather frequent replacements, so its not too practical solution. This year, we made a small reconstruction of the pond, made a small brook with waterfall, using the output of the pump. Since reconstruction, i didn’t see green water algae even after many hot days. The water is crystal clean now, like in some alpine lake. Before, when we didn’t use a pump or used the pump output go directly to the lake, without UV lamp it did not prevent green water. This small stream + tiny waterfall is trully a win-win – it does look and sound great and does the perfect job in water cleaning…

    • I am surprised the brook and waterfall made that much difference, but all of the rocks in the brook are now covered with bacteria, and they are helping to keep the water clean.

    • Diana Restifo says:

      Hi Robert,
      We have built a pond about 19 feet by 12 feet, with depth from 1 to 3 feet and lined it with the 45 mil EPDM, in Pennsylvania (zone 6). As we start adding plants, do we have to be concerned about the roots eventually damaging the liner? Thanks for your great posts.

      • some sources say this can happen – but I doubt it. I tried to use a utility knife to puncture the liner – just to see how easy it was to get a hole. It was damn hard. I doubt roots can puncture it.

  56. Sandra Lewis says:

    Oh!! I love this! Six months ago I stopped putting chlorine in my 20′ by 40′ swimming pool and turned off the pump. I had done lots of internet research but only found one place that said it was possible to go pumpless.

    That gave me courage and knowing that it was reversible if it was a horrible disaster clinched the deal. It was pretty ugly at first but I was determined, and impatient. The second month I threw in a few big scoop shovel fulls of rabbit manure to help “feed the bacteria” I wanted. Bad idea but not fatal. Now my ammonia levels are still too high for fish to live in but my plants are fantastic.

    I didn’t want to fill the pond with dirt or stacks of tires or bricks as some had done but needed a way for the plants to be in shallow water. Then on you tube I discovered floating islands for ponds.

    I adapted them and went out hunting for wild plants, begged plants, and even bought a few. Now I have lovely floating islands that sail around in the breeze like swans gliding. Some plants like the duckweed and water primrose just go crazy, trying to take over, but I like them as compost around my fruit trees. I just rip it out and throw it at the trees’ base. My ammonia levels are slowly coming down and soon I’ll be adding some catfish, bluegill, and perch. Even now the frogs, dragonflies, and other small creatures are moving in.

    I wish I had found your blog when I first started. It’s wonderful. Thank you so much.

    • nancyleep says:

      Sandra – thanks for the link to the plant islands – I watched several videos and am looking forward to trying this. My pond needs so much water – the liner has been repaired and there was no problem when the filter is off and the waterfall feature isn’t running so I suspect there is leaking in the inground piping. So next summer, I don’t want to use the waterfall feature – just the pond without a filter. This is so helpful.

      • Sandy says:

        I’m so glad the island links were helpful. I’ve learned a few thing building my own islands.

        +Don’t put dirt in them. I’m still trying to figure out how to clear my water of the suspended dirt.
        +If you buy plants in pots they’ll be fine if you just take them out and dump them in your island.
        +The plants GROW! Duh. Allow enough room around plants that will get bigger so they don’t flip over. (Don’t ask. lol)
        +Mint LOVES growing on islands.
        +Don’t try fancy shapes. Circles are much more stable.
        +A dollar store laundry basket with Pool noodles zip tied around it is an easy island.
        +Use black zip ties. Lots of them.
        +If you have free floating islands they will decapitate your lilies.
        +If you’re planting standard cattails make a deep (couple of feet) basket so more of them is under water to balance the height.
        +So far I know Papyrus, Pickerel, mint, Water Primrose, Japanese Iris, Horsetail, and Knot weed do well on my islands. I also put some little trailing house plant things in and they are happy now but I don’t know how they’ll winter.

        I scavenged my Water Primrose, cattails, horsetail, and Pickerel from wild ponds and river back waters. Begging ads on Craigslist and freecycle got me some donated plants, and I got Mosquitofish from the county. A kind, overstocked Koi breeder gave me a great deal on some of her less beautiful ones, and the feeder goldfish I got at Walmart are doing fine. My duckweed was beautiful. Like a lush green lawn, but now it’s almost gone. I don’t know if it’s too much sun, fish eating it, my islands hogging the nutrients, or what.

        I have mixed feeling about the duckweed. It was so beautiful and I was harvesting it every few days to put around the fruit trees. On the other hand it’s a lot nicer swimming without getting coated with it, inside and outside my suit. And harvesting might have gotten old after a few months. Right now though I’m spending more time in my pond than I did when it was a pool. There’s something really neat on a hot day about combining gardening and swimming. I get to stay cool and feel virtuous instead of lazy. The difference without the drying of the chlorine… I LOVE the feel of the water, even if it isn’t pretty and crystal clear YET.

        I made an “artificial reef” for smaller fish to hide in by taking a roll of the blue swamp cooler pad and running baling twine in and out lengthwise down the center. Then I pulled the twine shorter to ruffle the matting and tied the ends together. It wouldn’t sink completely so I tied a rock to the baling twine to sink it. It seems like the fish enjoy it. I think it also makes a nice home for good bacteria and it’s covered with algae so it looks natural.

  57. Deepak says:

    I have a pond space which is 30×20 feet. It is in a rural area. Agriculture land.
    The area inside this so called tank that I call has been cemented so that water does not leak out. Also it is in open land.
    I want to keep fishes, and creat a low cost ecosystem for the fish to survive.
    Please guide how to go about it. I was told by a friend that in 8feet deep pond plants can’t be kept…a filter is very expensive here…
    How do I go about ?

    Dr Deepak

    • I have never worked with a concrete pond – so can’t be of too much help. The concepts I have outlined in the post should still apply.

    • Peter says:

      Hi, i have concrete pond in my backyard myself. I think 8 feet deep is rather too deep for most pond plants. You can make however small islet in the middle where water is maybe just 3-4 feet deep and plant water lilies there. for swamp plants, you need area with 0-1 feet.

  58. Mia says:

    Wonderful post! My friend bought a 150 year old house that had been empty for a few years. In the garden was a smallish pond with large goldfish living happily in it although there was clearly no filter, no bubbler, no human to feed them. I always wanted a goldfish pond, never wanted the pump and filter, so I was thrilled to learn about this functional little system.

    Although I have kept natural planted aquariums (soil on bottom, heavily planted, no filter or aeration) for many years, I never made the leap to thinking a manmade pond could thrive in the same way until I visited my friend’s. Now your post makes me think I might be able to have one of these beauties myself. Thank you for sharing!

    • Twenty years ago – long before ponds, I also kept a 6 ft long aquarium in a natural state, for several years. Full of plants, and some fish, but no air and no filter. Just changed 1/4 of the water once a month since we had very hard water.

  59. L says:

    Thanks for this article, added a few plants to my pond and within a week noticeable improvement!

  60. Tara Kreiner says:

    I just put in a small preformed pond (130 gal.). I have a toddler so I didn’t want to start out with anything too big. I am an avid gardener, but have never done a pond before. I would rather not do filtration, but will a pond this small do ok with only plants and fish? We have a small school of minnows, and 2 goldfish, and I am getting ready to purchase some plants. It is full of algae, but not stinky (yet). I am planning to purchase a water lily..what all would you recommend for a pond this small?

    • Tara Kreiner says:

      by the way, I live in Fullerton Nebraska – hot summers, cold winters.

    • As far as plants go, use native plants that grow in your area. I like Iris, except for the yellow flag iris which has become invasive in many areas. Two species of bull rushes have naturally seeded in my pond.

    • Anne says:

      I have a 50 gallon thats been going for some years now. I live in houston so I don’t have to worry about winter weather like you would. I think being 130 gallons may be better getting through a long winter though. Even here I put in a heater during our several 25Deg F days , but that was only because I have platys in the pond. Platys don’t do to well much below 60. Also my preformed pond is not in the ground completely, so the water is not as protected.
      In my 50 gallon pond I have dwarf papyrus, cork screw reed and spikerush. I have hornwort as a floating submersible plant and two dwarf water lilies. I also have a solar water pump that only cycles the water over some stones when the sun is out. This set up has worked really well for me all these years. I also have a bunch of ghost shrimp too. Hopes this helps.

    • Anne says:

      BTW if you have no plants in there at all for sure get some hornwort. it is a native North American plant and does an awesome job of conditioning water and helping it stay clear. Plus it gives your fish a place to hide and breed. Horse tail is another great bog plant too for keeping the water clear. The plants are your “filters” for the water. I wish I could send you some pictures of my little set up.

  61. F. Kennedy says:

    Thanks so much for this blog!

    We want to know how to maintain a low-mosquito pond without a bubbler, if it is even possible.

    This spring we began ‘naturalizing’ of the back third of our small, shady, suburban backyard in Maryland. We’ve installed elderberry, various viburnum, fern, blackberrries and a variety of native wildflowers. Water from our driveway and house has been directed to the area. As part of this effort to attract and sustain wildlife, we had a tiny pond (4’X8′) with liner installed. It is shaded, has a bubbler, a couple of submerged plants and horsetails at the edge. Within the first few weeks, we’ve been rewarded by two new resident tree frogs and have been visited by a great blue heron and a pair of Baltimore Orioles.

    Now we’ve learned that frogs require still water, so we want to remove the bubbler. While we’re waiting for the frogs to show up, we’re concerned about breeding tons of mosquitos in the meantime. Unfortunately, since the little brown bat population plummeted a few years ago, the mosquito population has only gotten worse.

    Advice, please!

    • A couple of gold fish will take care of the mosquito problem. By the way – bats don’t eat many mosquitoes – that is another myth. They prefer larger insects and only eat mosquitoes if they can’t find more suitable food.

  62. Diana Restifo says:

    Great site, thank you! My husband and I would like to build a small natural pond (without a pump!) on our rural property. He’s handy, so we’ll likely do all the work ourselves. One question I have is, can a small pond support a reasonable amount of plant and animal life? We are considering something under 100 sq feet. Another question is, is it fair to assume that a liner is needed to keep to pond from leaking? We live in the northeast U.S., and our soil is fairly clay-ish. Thanks much. Looking forward to more posts.

    • A small pond should work the same as a larger one.

      Will the clay soil hold your water? That depends on the clay and your water table. I have a natural pond (ie no loner) that is 20 ft higher than the lowest part of the land right next to it. It holds water just fine. We also have clay soil. However the water level does drop over the summer, probably do to a combination of evaporation and leakage. by end of August it is usually dry. Try digging a hole, and filling it with water and see what happens. If it runs away you will need the liner.

  63. Davina Miles says:

    Hi I live in Suffolk UK, and have had my small second hand plastic pond shell of approx 3′ X 4′ for 10 years. It has always had a large water lilly (too big for the pond size really) which came with it and I have had out twice and split down creating spare parts to sell on. There is a cluster of Pond Iris in one end and oxygenating plant the other end which during Summer is constantly being thinned out as it grows rapidly. Never had filters or anything on the pond and never had an algae problem. Always had at least 1/2 goldfish and numerous frogs took up residence and spawn every year in March. I have taken out sludge twice in these 10 yrs and have wondered about if there is a mechanical way to do this or not and wether or not a filter would help. I have never fed the fish either as I have always believed they must feed on natural provisions. The water is clear unless stirred up and never had a problem with smells. It looks like it is ready for another de-sludge and was considering a filter purchase but now upon reading your post I don’t think I will change anything I’m doing. We have temperatures here of between -1 /30 degrees and the pond does ice over for only a few days at the most but the fish survive to my amazement.

  64. I just finished digging a hole for a natural pond in our backyard. It’s approx 10×13 feet and around 2 feet deep at the deepest point. I plan on getting a liner next week and then filling it up. I have access to a few real ponds, do you think it would be beneficial to add some water from the real ponds to my manmade pond? Will it help control algae?

    • I doubt that adding water from a real pond will help control algae. The water from a tap has very low levels of nitrogen and does not support algae very well. water from a pond would have higher levels of nitrogen.

      Adding water from a real pond might speed up the colonization of the new pond with life. But that will happen in any event all on its own.

  65. Andrew Fries says:

    I’m thinking of having a pond dug on my property and not a small one, probably about 2 acres. I don’t want to have any maintenance of the pond and the only thing mechanical we want is possibly a fountain. The water table at my property is about 2 1/2 feet down so that should keep the pond nice and full without a liner. I’m doing this to keep the water from setting on my lawn in all the low places and I’m hoping a pond will draw all the excess water into itself. Should we do anything with such a large pond? I won’t be adding fish, but I’m sure our kids would swim in it. Any suggestions and ideas would be greatly appreciated. Our design is a larger L shaped pond with an island gazebo and our weeping willow on it with the island connected by a bridge to the hill by the end of our house. Thank you.

    • I have no experience with large natural ponds so I am hesitant in giving any suggestions. But since it will be natural with no liner, I can think of no reason your idea would not work.

    • Al Colley (retired from Auburn University) says:

      If you can plant one weeping willow in that low spot in your lawn where water stands then in just about six months to a year you will not have that standing water problem. I lived in an area a few years back where the entire lawn was bare and the water was so bad no grass would grow so I planted three weeping willows and in a couple of years we all had beautiful lawns. Weeping willows will dry up an area quickly.

  66. Anne says:

    Love this blog. wish I could upload a picture of my going on 4 years 50 gallon pond. Its full of bright orange platies that I never feed. The only unnatural thing I did this winter, was to put a heater in the pond on the lowest setting to keep the platies alive. On the few nights that we had the temp drop to 20 I went out to have a look. All the platies were hanging around the heater like kids huddling near a fireplace for warmth. LOL

  67. Brooke Q says:

    I am so excited to find this post! My husband and i have a 30×80 greenhouse that we are turning into a food forest. We had an old tub on the property and we decided to turn it into a small pond in the greenhouse. Because of the location of the pond within the greenhouse, we don’t really have the ability to use a filter. I definitely know I need to add more plants, but my husband thinks I’m in for a constant battle due to the heat of the greenhouse. I’m working on a shade structure for the pond, but am I crazy? Will everything just get too hot? We are already starting to grow heavy algae. Any help would be greatly appreciated.

    • I have never had a pond in a greenhouse. Algae grows better at higher temperatures so it will be more of a problem. Give it a try and let us know.

  68. Kerry says:

    I am also converting and old pool hole into a fishless pond. I am planning a waterfall at the deep end (approximately 6 ft deep) and a couple of aerators/bubblers in the shallow end (8 inches deep which will gradually slope down to the deep end) There should be 50% plant coverage on the shallow end. Is it okay to swim in the deep end? I have seen some natural swimming ponds but no one seems to have any good info on details.

    • People swim in lakes – clean ponds are no different. What I don’t see in your description is the plants along the edge. You need enough water plants to keep the water clean. A lack of fish certainly helps.

  69. Debbra Davis says:

    Wow! I am amazed at your knowledge, I have skimmed over several sites and end up confused, I came across yours and how refreshing to read your info and comments. I live in Ky. Thank you so much for the info.

  70. Heather says:


    We just moved into our home and there is a man made pond that was untouched for 2 years. One side has plants and lily pads other nothing. The pond is full of leaves etc I know nothing about ponds and I am overwhelmed where to start. Any advice?


    • Why not do nothing. Watch it for a year and see what happens. Once you better understand the pond, and what you want from it, you will be in a better position to do something that makes sense.

  71. Angie Watson says:

    I have just found your page, because having just removed winter leaves and muck from the bottom of my pond here in Bristol England, and looking to see how I can remedy the cloudy water, I came upon your lovely blog.
    In two days time I’m actually coming to visit my sons in Toronto and would love to see your beautiful pond if you open to visitors.
    I can see that there are many enthusiastic gardeners in Gwelph – I lived in Toronto for ten years but never visited that area.
    I did find a baby newt in my pond and know there are frogs and dragonflies visit each summer, so it is quite healthy. I’m reluctant to put chemicals in but do you think that Barley Straw may help?

  72. Margot Brinn says:

    I wish I’d read this BEFORE building our small pond as I didn’t build a wide shelf for plants, but oh well. At this point I would like to hear what pond plants you recommend.

    • That depends very much on climate and personal tastes. I like iris – but not the invasive yellow flag iris. I am adding some new Louisiana ones this year. I also like bull rushes which have seeded naturally. In my smaller waterfall I like marsh marigolds.

      Water lilies to help cover the central open area.

      I don’t bother with annuals – don’t see the point of buying plants each year.

      • Julia says:

        Hi — Great post! I have a couple of questions. Doesn’t your waterfall oxygenate the pond? Is the key to keep the waterfall small enough not to introduce too much oxygen, so the anaerobic bacteria can do their thing? Without a pump, how do you accomplish the waterfall? Bell siphon?
        Secondly, I received a free small rigid liner, that I am going to dig a wide boarder around, and put in about a foot below the ground level, to create a planting shelf. Our yard is very close to the Patuxent river, so we have maybe an inch of topsoil over a bed of sculptable, red clay. If the rigid liner sits right on top of clay, with this clay planting shelf around it, will I still need a rubber liner over the lot?

        • I think you are getting the two systems mixed up. The large pond does not have a waterfall or pump. The smaller pond does have a waterfall and pump, but no filter. A waterfall does oxygenate the water which is a good thing because you want aerobic bacteria decomposing the organic matter, not anaerobic bacteria.

          Not sure I follow your design. I think you are putting the hard shell below ground and then using the ground as the planting shelf. If this is correct you do not need a liner if the water does not go above the edge of the hard shell. If the water goes above the edge, then you need a liner to keep the water in place. If the planting shelf is made from clay it might hold the water well enough so you do not need a liner.

  73. Carina says:

    Love your blog and this post is especially reassuring. I’m not far from you, in SE MI, and am entering my fifth year with a very small natural back yard pond. I have plants filched from nearby rivers and lakes, and three comet goldfish. I “aerate” and top it off occasionally with a good sprinkling from my garden hose, do not feed the fish and since I put the five feeder fish in there in spring 2011, I’ve only lost two – the remaining three are the original survivors and 6-8″ long now.

    I do have a fence around it (because the dog would destroy it otherwise) and throw netting over the top in fall to catch the bulk of the dead leaves. Otherwise it’s a nice, low-maintenance and self-sustaining little ecosystem that attracts frogs, dragonflies and interesting bugs. Found your blog while looking for information on building an adjacent, larger pond this spring. I really don’t want to have to fuss with a filter and pump and most of what I read online (and the pond supply store guy) tells me I must have one. I’m glad to know they’re wrong, and I’m looking forward to digging a larger pond as soon as it quits snowing!

  74. Jo says:

    You offer some excellent insights based on what I’d call scientific information into something I’ve played around with myself but on a much smaller scale. A huge THANK YOU for going to the trouble to share what you’ve learnt. I have a question for you, and should start by saying I live in North Queensland, Australia (in the heart of the tropics). For several years I have had three small “pot” ponds (two are ceramic and one is poly), the largest is 1.2m diameter and 600mm deep. I specifically didn’t want the hassle of filtration etc so I put an “oxygenator” plant in each which has grown to epic proportions, to the point where every so often I reef handfuls of the stuff out so I can actually SEE the fish. I started out with just 8 fish which I’ve never ever fed, and now have probably hundreds in each pond as well as tadpoles, frogs, dragonflies and goodness only knows what else. I have recently looked into buying a pair of geese but am not enamoured with the idea that I need to buy an ugly blue plastic kids wading pool for them to swim in which is the locally recommended solution. Instead I’ve sourced second-hand two large pre-formed poly ponds that are each about 2.4m x 1.6m x 60cm deep, they have an irregular shape and also have “shelves” for plants with the deepest section roughly in the middle. My plan originally was to set the ponds into mounded up dirt to support the sides, after cutting a hole in the bottom of each and inserting some kind of capped pipe so that I can regularly drain the water out to keep it clean. But … each pond holds 1250 litres of water which seems incredibly wasteful even if I pipe it out into trees in the orchard. I’ve looked into pumps, but I’d only really want to drain the really ikky stuff of the bottom and I don’t know if the pumps work like that. Plus, pumps sound like a lot of work – just one more job to do on weekends when I could instead be sitting there enjoying the ponds and my geese. Instead I am wondering about stocking each pond with my oxygenator plant (bacopa caroliana) which is super pretty and obviously thrives here, and adding a few handfuls of the many fish I already have … and waiting to see if the ponds can manage, like my others have, on their own. My question is this – if the geese bathe in them regularly and presumably poop in them too, do you reckon the poop might throw out the nutrient balance too much? Or is it all a question of how much poop and how big the ponds are – in other words, just trial and error? I guess there’s also the question of what the geese – and their beaks and clawed feet – might do to the plants but I’m sure I could do something to help the plants get established bit by bit eg planting at the opposite end of where the geese will likely get in and out. Any advice you can offer would be greatly appreciated.

    • I think it really comes down to how much poop the geese leave in the water. I might start by leaving out the fish since they also add nutrients and with the geese you don’t need more. It also depends on how much time the geese spend in the water. I don’t know geese very well, but I think they spend much of their time on land. they might actually add very little nutrients into the water.

      People who grow Koi suggest putting a hole in the bottom of the liner, and attaching a pump to the bottom. this lets them suck out just the junk that has settled on the bottom. This is usually done with a liner – not a fixed plastic pond. the key is to get a good seal at the bottom. I considered this for one of my ponds, but in the end decided I just did not trust the seal.

  75. Shirley says:

    Thanks so much for this; I’ve had what I call my “still pond” for 16 years–two ponds at two homes. Never used a filter, never used a pump. Keep the electricity and pipes and tech away from my shangri-la, thank you very much. My pond has over a dozen various plants growing in it, at the bottom and on the sides, not to mention algae at the bottom. I do empty it a few times each season, dredge it a bit and fill with fresh water. This must be done to cut away the incredible tangle of plant growth. Frogs come and stay and leave behind tadpoles; dragonfly nymphs abound, a garter snake resides close by and keeps the frog pop down. I also have goldfish which multiply so fast in May/June, that I give away 4 dozen at the school I teach at. I love my filterless, beautiful pond and it loves me back for not making a fuss.

  76. henry ingemann Provstgaard says:

    Dear Robert Pavlis

    Thank you for telling in a way so we understand what should be common sense!

    Ill making a system with waterfall, stream, small and big ponds on a steap hillside down to the beach at a resort on Ko phangan and it helped me a lot to read your blog!

    Looking forward to see more about floating island plants!

    Kind regards
    Henry Ingemann

  77. Kylie says:

    Thank you for sharing your findings! It has inspired me more now. I’ve lwys wanted a pond but have always seen them as too much of a hassle with filtering and pumps and other jargon that I don’t have time for. It seems you have made a self sustainable pond that requires no maintenance. I am planning on making one that is only about 4ft wide. Would a big plastic based container change anything rather than using the lining? Obviously I would still need to add rocks to make shelves to increase the surface area. Is digging a hole and using lining the only way to go? Thank you

    • There is no real difference between a hard plastic container and a liner. The problem with hard plastic is that you are limited in size. If you take a 4 ft pond, and add rocks for a shelf, you will end up with a 2 ft pond – which is getting quite small. Liners allow you to make ponds bigger. You could use a 4 foot pond, and have the shelves in addition to this, making the liner size 6 ft.

  78. Johnathan says:

    Hi. Im super excited to have read this article, it was filled with tons of information that I needed. I too am looking for a way to start a pond without filters and pumps. This is my story… I have a 10,000 gallon pool just sitting in the back yard, full of everything under the sun. I have leaves, sticks, snails, minnows, and who knows what else. Theres quite a bit of algae in there as well. I bought a pump that would move 250 gph of water and microabial algae clean. I dont mind leaving the pump in there, as I am running the water into the preexisting water fall. I felt this would help get the water moving a bit. I wanted to add gravel and plants into the water fall, this I would hope to help filter the water as it comes up through the gravel and plants. What other advice would you have for me to get this pond up and running successfully. How many plants, what types, and what grows at 7 ft deep where all decaying leaves and such are?

    Thank you kindly.

    • Pumping water through a gravel bed should be a very good filtering system. I almost added one to my water fall, but decided against it for the reason that if it ever got plugged, and they do, it would be a big job to clean out. For me there is also the issue of things freezing and cracking in winter.

      I don’t know of any plant that grows at 7 feet deep. You could build up islands to a more shallow depth and plant on those. You can also add a floating island which I just researching now. the floating island would allow you to have more plants using the nutrients in the water, and cover more surface area keeping sun from the algae.

  79. elitechi says:

    Hi…im so happy i found ur blog…i am really looking for miracles to create a pond without pumps or filters or other machines or tubes ‘coz it will cost a lot…heheheheh… i am about to make a pond this summer vacation… in ur post, you said “pond plants are not in pots” and u have those planting shelves… is it ok if i’ll just put the plants which are actually in pots into the pond? Or is it really necessary to remove the pots and just put the plants into stones wthout any soil? thanks! 🙂

    • There is nothing wrong with using pots. What you will find is the plants will start to grow outside the pots over time. When they do it becomes difficult to get them out of the pots in the future, but the plants don’t care if they are in pots or not.

  80. Mischa says:

    Brilliant article. I have been seeking clear concise information for years. My man made pond is approx 16 ft by 3 ft with depth about 12 to 18 inches,I have a pond with a lining, 12years old now.
    I was encouraged to get a pump with centre fountain.I have about 8 goldfish born in the pond. Some have died or plucked by a Heron! The pond is in full sun pretty well all day.
    Last year my pond became full of what looked like soapy bubbles. I didn’t know what to do. Finally I applied a powder to breakdown the leaves and rubbish at the bottom of the pond.
    Only when it got colder did the foam finally disappear.
    I am not sure that was the right thing to do and still very unsure what to do this year. …?

    • Not sure why you have bubbles. The decaying material in the pond will produce gases, but these usually just escape into the air–especially if you have a fountain going. Sorry I can’t help.

      • Rosie says:

        I started getting bubbles in my water when my algae started to die. If you put any kind of algecide in the water this is what happens anyways.

    • Shela says:

      I do believe your goldfish were spawning, that’s the foamy stuff you saw on the pond. The first time I saw it I too wondered what it was and was horrified to think soap had somehow gotten in my pond. I tried netting it out, The second year it happened I just left it because no harm had come to the fish the year before, then to my amazement about a month later we counted almost 50 baby fish, hiding among the rocks and plants! Hope this helps

  81. Joseph Crawford says:

    I am in the process of digging a natural pond and found this post extremely helpful. The water table is so high here and the soil is so clay heavy that I feel this may make it possible to do without a liner. It is half full the day after digging it out without any supplemental watering… I have some questions regarding a 1000 gallon pond, 3 1/2 feet deep at maximum :
    1) If my water level fluctuates by about 10-12 inches during our dry season, are there any plants I should specifically avoid that don’t do well with this fluctuation?
    2) What are you thoughts on no fish at all, and just keeping a turtle/frog population in place?
    3) I was going to put some sand in the bottom as well as occasional large and small rocks. What are your thoughts on decaying wood floating around or dipping in from a shore line?
    Thanks for your time and expertise!

    • Water plants are used to water fluctuations. What is important is that at the low levels, the plants are not sitting on dry soil. As long as the roots stay wet they can take the drying. My pond will go down by 8-10 inches if we don’t get rain.

      You don’t need fish. In fact I am quite sure that my fish eat most of the tadpoles in my pond. If I did not have fish i might have a lot more frogs. One thing to watch out for are mosquitoes. Fish do eat mosquito larvae and keep them out of the pond. Other wild insects will also do this, so long as your pond does not breed mosquitoes you don’t need the fish.

      If you ever decide to clean out the bottom, the sand and rocks in the bottom may be a problem. It is hard to clean with them there. Large rocks are no problem an I think they are important for making the pond look natural. Real ponds have rocks sticking up in the water – most man made ones don’t. when I made my pond I made sure to add some large ones right in the water. Logs would also be a great addition, and wildlife will love them. Turtles, if you get them, love to sun on them.

  82. jeff says:

    I have 3 care lot and I am researching to build a pond. I love to have nature pond without even liner, but some people said it will hold very low water during winter (Florida), I am not sure if I dig deep pond and opt opt out the liner is good option? I have to go 15-20 ft deep. I want to do 30×50 ft pond.

    my second question if I use the pond water for irrigation, would this be very good for my garden and clean the fish waste? I will have mechanism to refill the pond (if I go liner but omit if I go 20 ft deeper)


    • Making ponds without a liner is a different story. Success depends very much on your local conditions. I suspect in Florida you can dig down and find natural water in many places because much of Florida is reclaimed land which is very close to sea level. In other places a hole will not hold water unless the soil forms a clay barrier. You really should get some expert local advice on the liner.

      Pond water, including fish waste is very good for the garden. You will be watering and fertilizing at the same time. This is provided that the pond is full of fresh water. In Florida you might get salty water coming up from underground if no liner is used — that would not be good for plants.

  83. Will says:

    Hi Robert, thanks for such informative article. Hope it would encourage more people to build pond the natural way.
    I converted my swimming pool into a natural pond, it’s on its fourth years now and have never used a single watt of electricity . Never changed the water either, and all is going well similar to what your pond.

  84. Diana C. says:

    Dear Sir, Thank you so much for your article on ponds without pumps. I will be taking your advice this spring when I (rebuild) my starter pond from last year. I just want plants – no fish, maybe a frog or two, a place for birds to take a bath. Now I know its okay to have less than clear water and plants without pots and dirt. Wish me luck.

  85. Belinda says:

    Hello from the Western Cape – South Africa. Thank you for the insight and authentic wisdom – I have learned a lot. Hmmm am busy developing a water pot that can host my waterlilies because my Bull-terrier thinks it’s food LOL – I am not so sure of not having the plant in a pot with soil but will follow your advice – God bless!!

    I love your pond!!

  86. BJ says:

    So good to read your post Robert! I created a large pond about 6 or so years ago and have been using pumps but the work they entail is too much! I’ve got a fair amount of plants and plenty fish and frogs too now. The look is green and friends all tell me I need to drain it and clean it but I’m with you – you don’t see nature emptying and cleaning natural ponds! Thanks again, great post!

    • abornet says:

      This is the best site for support for no filter ponds. My little 50 gallon pond is still going strong it a morph of some smaller ones I had for some years. Still have my ghost shrimp from way back too! It is full of hornwort, dwarf papyrus,dwarf cattail a few dwarf liliys. Has some platys to eat the mosquitos. My only cheat is a very small 12$ solar pump to occasionally circulate the water. Only works when the sun is out and I dont fuss over it at all. The best thing was this summer when I was thining out the hornwort I found fresh water sponges growing!!! How cool is that! This little pond never fails to surprise.

  87. Phil says:

    Great article. I was just arguing with the old man about pond filtration – turns out he could be right.

    We had a kidney shaped pond about 10 x 5ft (thin point of kidney) x 2ft (average depth). with a waterfall and little fountain feature. The only “traditional” filter media was the sponges on the small pump intakes. we had one reed sort of plant that overgrew the plastic bowl and eventually the reed and plants from outside the pond grew through the liner and basically that was the end of the pond. It was full of algae up to its new water level and the reed had grown roots through the bottom 6 inches of the pond.

    A couple days ago while my father is in town, I convinced him to help me rip out the reed and now I’m contouring the bottom of the pond again. We’ve decided to redo the base with cement to help safeguard against incoming roots. We’re keeping both the fountain and waterfall and we are discussing at the moment whether or not we need some sort of proper filtration.

    I’m hoping to heavily plant this pond and I’ve been planning to create three boxed out sections. I’ve decided to try and grow some aquarium plants in my outdoor pond. – hygrophila, Cabomba and some assorted crypts and swords. the planter boxes will take up about 80% of the pond but it will take a while for it all to grow in. I’m half expecting the crypts and hygo to just die off. the cabomba is hardy as and will probably take over if I dont prune it – assuming it survives winter. – They are “tropical” plants.

    I think it’s safe to assume algae will be a problem for at least the first few months. the pond gets lots of light and being summer it’s more intense. I have two goldfish that I rescued from the old pond/swamp that will have to go back in and I’ll probably have to feed them at least a little for the first few days.

    after the ponds established a little better I will add a dozen guppies and hope they breed like mad and in turn feed the goldfish too

    I guess Im wondering if;
    A) im doing something wrong
    B) If having a pump intake at the bottom of the pond is a bad thing, and
    C) will a heavily planted pond cope with a hundred guppies without proper filtration? (they breed like crazy)


    • What kind of pond liner are you using? I used 45 mil EPDM and that stuff is strong. I would be very surprised if plant roots penetrate it. When it comes to the liner–buy the best. It is just too much work to redo a pond.

      I have breed a lot of fish and grew many aquarium plants in the past. Most are tropical and I don’t see why you would add them to the pond unless you have extra. As you say most are tropical and they will die in winter. Why not get something that will survive?

      I’ll tell you a bit about one of my aquariums. It was about 5 ft long. I put chicken grit in the bottom–much cheaper than aquarium gravel and just as good. I planted it heavily and added some fish. No air, no filtration. In 5 or 6 years all I did was replace some water on a weekly basis since my water was very hard and the evaporation made it even harder. Plants thrived and fish thrived and bred. It had very little light so algae was not a problem.

      Algae will be a problem if you have too many fish or not enough actively growing plants. You can expect it to be a problem in the first year or two. One thing you can do is cover the surface of the water with either floating plants or even Styrofoam until things get established–or just live with the algae. algae is a sign of a healthy pond–we just don’t want to look at it.

      You plan looks good.

      I seriously looked at putting a pump intake at the bottom of one pond. This is very popular with people with koi because they are such messy fish. I think it works fine, but I just could not bring myself to poking a hole in the bottom of the liner. It just seems like a leak problem in the making.

      Do guppies breed like crazy? I know they do in an aquarium–used to have lots. But in a pond outside, you tend to get things like frogs, and they will keep the population down. but to answer your last question, there is a balance between fish poop and plants need for nutrients. It is real hard to know when you have too much poop. It is something you just have to try. If the plants are well established and growing well, and you still have too much algae–you need to reduce the number of fish or get more plants. Find a fish friend with some large fish and they will gladly come over a couple of times a year and get the extra guppies for food.

  88. Sara says:

    Hi I have a square pond with straight edges about 6 ft deep and 4 ft wide can I have a natual
    pond there is a tree near it and it doesn’t get full sun for very long i would love to have some wildlife use it thank you Sara

    • Robert Pavlis says:

      I think there are differences between ‘natural’, ‘natural looking’ and ‘containing wildlife’. A square pond with straight edges will never look natural but it can have wildlife in it. The square edges prevent you from having plants at the side of the pond except for potted ones. You can however, plant in pots on raised supports. Try adding a variety of plants to see which ones will grow in the shade you have. More plants = more wildlife.

  89. Anne says:

    So Awesome to find your site! There is essesntialy no information for keeping a truly natural pond. I have been keeping small non filtered, nonairiated ponds for 10+ small I mean any where from 11 to 100 gallons. Every one who sees them is stunned at how clear the water is. Its really just getting the balance between bog plants, water weeds and critters.

    It all started with a container pond in a large plastic planter. Fast forward 3 years. The container pond completely negelected other than infreqent additions of water just cause I was infreqently watering in that direction. It over grew with horsetail reed. The plastic was faded, full of leaves twigs etc when I finally decided to get rid of it figuring it was only a haven for mosquitoes.

    When I dumped it over to reclaim some of the horsetail reed I noticed movement inthewater on the driveway. It was some generation of those little clear shrimp I had put in there 3 years earlier! I was stunned that those things had lived in a small sustainable environment with no help from me and quickly tried to save as many as I could find! I felt guilty, like I was some asteroid that destroyed their little planet ! I’m sure the rootbound horsetail reed played a big part in creating and maintaining that little world .

    That little event convinced me how impotant bog plants are and how easy they make it to keep a pond. The progeny from those original shrimp are in my main pond and I have 4 other ponds full of bog plants. None with a filter and so much fun to see what has taken up residence.

  90. Lena says:

    We had a small 4x4x3 ft pond in our old house and we figured out how to use a pond master basic filter along w a barrel w some cylindrical things in there. We now live in a new house and 1 mo ago we had a landscaper build us a beautiful natural pond w river rocks lining the bottom and 2 waterfalls. It’s about 7 ft x 6ft x 3 ft deep. He gave us algicide to put in every 2 weeks. There seems to only be a skimmer and under it a white porous material, doesn’t seem to be much of a filter. 1 mo into it the water is GREEN GREEN GREEN and murky and we can’t even see the fish OR the beautiful stones that lined the entire pond. The landscaper keeps saying its bc I’m feeding the fish or bc I don’t have enough plants. But I think we need at least some kind of filter don’t we? There are some type of filter behind the waterfall but nothing he told us to clean. I have asked for a filter and asked for a uv light and he says I need to trust him, the pond will equilibrate. (Your article is giving me some confidence in his advice!!)

    But how will it get clearer if it’s full of algae and it’s hot and sunny and nastier day by day w/o any filtration. The white sponge thing he said to clean once a year. He said he offers a pond cleaning service for $500. I had to use his pump to drain the pond for a party and clear the water prior to the party and a day later it was nasty and murky again, he said the algae came back bc I didn’t drain it enough.

    So how long will it take for the water to get clear again. Right now we can’t see even the shallowest stones 6 in deep anymore or the fish. I plan to get more plants next year but seems like a lot of $$ to get them only for a few more months. Advice? Should I trust it will all equilibrate? How long will it take. The neighbors loved the pond when it was new and I’m embarrassed to show it now bc it’s so murky!

    • Robert Pavlis says:

      There is no need to feed the fish–they will find food including algae. Fish food leads to fish poop which leads to more nutrients in the system which leads to more algae.

      The plants you want are permanent plants–perennials. It sounds like you don’t have any now and even once you get them it will take them time to establish themselves. The bigger they get, the more nutrients they will use. With my pond, the amount of algae gets less each year.

      It is also natural to see an algae bloom each spring. As soon as things get a bit warm, algae will start to grow. The plants are a bit slower to get going but once they do they take the excess nutrients away from the algae and they die off–or at least get reduced in number.

      For natural control the plants should be taking up half of the area of the pond, and water lilies need to cover 2/3 of the surface to keep sun out.

      Algae grows very quickly, but if it is completely murking in a day, the water has too many nutrients. don’t feed the fish.

      • Lena says:

        Thanks. This is very helpful. In our other pond there was shade on all sides so this open pond is new. I didn’t realize I needed that many plants. It seems expensive to invest in plants so late in the year but I plan to do so next year, though I guess I will buy some perennials now.

        The water did clear up after adding algicide two weeks in a row and the cooler, cloudier weather. Our pond is about 1000 gallons and has 6 comet fish and 4 small goldfish. That doesn’t seem like too much does it? It’s so fun to feed them and they are already trained to come as soon as they see me but I will try to minimize feedings. We used to feed our other fish 2x a day in our old pond so this is a new thing for us.

        I will look at your website for the right plants to get. Right now we have hyacinths and water lettuce but they only cover 10% of the pond, if that. Thanks so much for the great advice.

  91. Rick says:

    A real pond, even one dug by a human should require nothing. Only a fresh water source like rain, a spring or ground water. The problem is people only make money by selling you things you don’t need. Nature will always be better then man-made BS. Plus, humans like to do things that are unnatural – and that’s were things get screwed up. As an example aquiculture. Not natural, and requires on-going inputs. Here’s what I would recommend. Live small, make enough money to pay bills, live locally, eat locally, and think globally. Be happy.

  92. Joe says:

    Will adding a red ear turtle to a pond make it harder to maintain? Found a kidney shape pond liner at a landfill in great condition, previous owner said he had purchased it but never used it. So I brought it home immediately. I live in Anaheim Ca. And I’ve been doing some research on red ear turtles. This pond will not be buried but will be above ground. I plan on buying those nice designed bricks to camouflage the outer part of the liner. I’m glad I found this article because I do not want to run any electrical lines to the spot I’m going to keep it (plus I’m a renter). I would like to just have it as simple as possible so my 4 yr old boy can enjoy it as he enjoys the two other tortoises walking around the back yard. What plants are recommended for a small size liner as mine and how many? Thanks so much.

    • Robert Pavlis says:

      You don’t say how big the pond is or how big the turtle is. Those are important numbers. Turtles poop and that pollutes the water. Put a big one in a small pond and it is difficult to keep clean. Put it in a larger pond and it is much less of a problem.

      Animal waste or even plant waste degrades over time adding nutrients to the water. As nutrients build up, algae will start to grow–especially when there is a lot of light present. This creates a slimy pond and some people don’t like that. The slime is actually healthy for the pond, but esthetically not pleasing. The best way to keep algae down is to add lots of plants. Waterlilies cover the surface keeping light out, and any plant with roots will use nutrients to grow. If plants remove all the nutrients, algae stops growing. You can’t have too many plants. For plant selection I would talk to some one local. I live in Ontario, and our climate is much different.

  93. Jimmie Pitt says:

    Jimmie Pitt says:

    I am about to complete my third pond. I have improve my design and filtritation systems over the years. On my present pond. I am combining mechanical and natural filtration because of my narrow sloped yard. The upper pond will be the bog/marsh pond and will cascade into the lower deeper pond. Each pond is 8×8 ft. The lower pond is 3ft. deep and has planting shelves on two sides. The upper pond which will be the marsh will contain 2 ft of gravel and lots of plants.

    Water lilies went in lower pond yesterday, I will plant the marsh pond as my work schedule permits. I will give updates as work progresses.

    • Robert Pavlis says:

      Sounds like a good design. I was going to put a filtering pond at the head of my waterfall. Originally I like the design where the water enters the upper pond at the bottom and perculates up through the sand. After a lot of reading I decided that such a system clogs to easily, and once that happens it is difficult to unclog. In the end I decided not to use one.

  94. Sabina Vaughan says:

    Thank you so much for the information. My husband and I want to build a pond in a natural low part in our yard. My little confusion is this…I don’t know how deep we will go. What about a shallow pond…say 5 ft..will water plants and fish do alright in this depth?

    • Robert Pavlis says:

      5 feet is not shallow. Most man made ponds are 2-3 feet deep. My large one is 4 feet deep.

      Plants like depths of 6 inches to 3 feet. Things like Iris and bull rushes like it shallow. Small waterlilies are happy at 2 feet, and larger ones at 3 feet.

      Ponds don’t freeze very deep. Once the surface is covered with ice, the heat from the earth keeps the rest of the water from freezing. Fish usually die from lack of oxygen. Dead plant material in the bottom decomposes and gives of CO2. When the surface is open this co2 can escape, but once the pond is covered with ice, it can’t. As it builds up, the fish die. Gold fish in my 4 foot deep pond had no problem surviving for several years. Last year it got cold early and stayed cold for several months. This meant the pond was covered with ice for a long time. The fish died. A simple solution which I will try next winter is to have a simple air pump going all winter. Even a small hole will allow the CO2 out.

      For gold fish in zone 5, I would aim for a depth of at least 3 feet. Warmer climates need less.

      • Zita Lovell says:

        Our pond is approximately 9X11 and 3 ft. deep In center. It has been established for 10 years. We have a waterfall and stream with a pump and skimmer setup. I really want to make it natural and not run the pump. I read your articles several times and took your advice. I have downsized on number of fish, put in more plants and I am trying to get more top coverage. I have also stopped feeding the fish. Our pond gets a great deal of sun. We did drain the pond this spring and clean it, and I put some chemicals in it to keep algae down because I am afraid to shut the pump off till I know the fish will be safe with enough top coverage to keep the water cool enough for them. I really would like your input to see if I am on the right track. I also put a couple small grass carp in to help keep things clean.

        • Cleaning the pond removes the important bacteria – don’t clean the pond.

          Don’t add chemicals. If algae grows let it grow. How else will you know you have an algae problem?

          • Zita Lovell says:

            We have lost 3 fish in about a week. They died for no apparent reason. Never had this happen before. Our water looks good. I did have it checked though. The PH was hi. The gal at the pet store stated that when the temps are extremely hot it takes oxygen out of the pond. She suggested taking the pond down a 1/4 and refilling. What do you think about this.

          • Warm water holds less oxygen – that is true. Replacing 1/4 of the water won’t change this.

            If the pH is high, the next question is why? What is the pH of the water being added? If the water being added has a lower pH, replacing some of the water will reduce the pH. If the replacement water is also high – which I suspect – replacing water will not change anything.

            Adding rain water will help. The pH of rain water is acidic – usually around pH 5.2.

            If your tap water is hard, the pond pH will go up slightly over time as water evaporates. In this case a change of 1/4 might help.

          • Zita Lovell says:

            We just lost another fish yesterday. We have had so much rain here I dot know how we could have a high PH. I only did this 1/4 water change. Last week. What is odd we have now spotted baby fish approx. 1 inch in size. We figured they would have all died like the big ones. Just received 4 inches of rain the other day. I am really frustrated. Have talked to a number of other people and they have not lost any fish. I have about 2/3rds of the pond covered with a sheet of insulation suspended above the pond. Lots of plants also.

          • Have you tried taking a live fish out and looking at it. Can you see and disease?

          • Zita Lovell says:

            I just remembered that a while back when we were fishing a lake we pulled some plants from the lake that are Arrow Arum I believe. We brought them home and I put them in a bucket of water to wash all the mud off. Then I set them on the pond shelf and weighted them down with a rock. Is it possible that something from them has killed our fish?

          • That is certainly possible.

      • Zita Lovell says:

        Mr Pavlis
        We ended up loosing all our Koi. I took a water sample to our DNR outlet. They concluded it was due to my adding 3 pieces of old dead tree limb pieces. It was for cover for the fish to get under and in. We were told that the wood continued to rot and decay in the water and give off bacteria and take oxygen out of the water. We didn’t suspect that since it had been in there for 2 years.
        My husband wants to know if we could just put a small bass or two, catfish and probably a couple small grass carp? Will they sustain in our pond with out their natural food source supplied by a lake. Referring to them being predator fish(bass,catfish). Do you have any advice for us?
        Thank you

        • I don’t believe the wood caused the problem.

          check the amount of space required by the fish as well as their preferred temperature. Provided you provide what they need to live and grow they should be fine.

  95. C. Odu says:

    I love your post and cant wait to try your method. Keep the information coming. Your logical approach to sustainability and self sufficiency is refreshing.

  96. Carol Clark says:

    We have had a succession of small backyard ponds for 43 years, none with filtration, so I found your new posting really interesting.

    Our most successful approach has evolved to keep the vegetation, especially the water lily blooms, out of the reach of hordes of city raccoons. In the most recent design, the flowers still get nipped, but the fish are happier and the pool requires far less maintenance. We clean the debris from the bottom once each year in the spring but no longer remove the algae from any surfaces.

    We have eliminated planting shelves because the raccoons simply tore out everything at the edge. The really shallow plants, acorus and irises, are wired in their pots to uprighted cement blocks. The cement blocks function as obstructions to prevent the raccoons from dragging the pots of water lilies by their leaves to the edge of the pond. The holes in the blocks have become havens for the fish when the raccoons take laps around the pool (really!!!). Now, reading your posting, I realize that the blocks are significantly increasing surface areas and we can try wiring the rhizomes directly to the blocks without pots.

    We still have too many fish since baby goldfish are as hard to give away as kittens. (The fish store no longer will accept them as shark food to avoid introducing disease from outdoor ponds.) Fortunately we have a friend whose setup is not favourable to overwintering his fish, so he’ll take 2 or 3 12” adults off our hands each year. Successful reproduction is limited by the large number of adults which eat the eggs, so just enough babies survive to replace the ones we give away.

    As for not feeding the fish, that may be difficult. My 99 year-old mother-in-law and all of the neighbourhood kids clamour to get their turns feeding them. The fish were introduced to keep down mosquitoes, but now they are pets and are a real attraction.