Animal ForageAquacultureBiological CleaningFishFood Plants - PerennialFood ShortagesNatural SwimmingPlant SystemsUrban Projects

Convert Your Eco-Unfriendly Swimming Pool into a Biologically Active and Attractive Fish Farm!

Could converting swimming pools into fish ponds be another way to increase food security as we head out onto peak oil’s downhill slope?

A Permaculture fish pond in development

Swimming pools get a bad rap in enviro-circles, and for good reason. They cost a great deal to construct – using a lot of CO2 intensive materials in the process – they waste huge amounts of water and energy for maintenance, use chemicals to keep them clear and ‘safe’, and they take up a lot of space that could be utilised for more productive purposes (like growing veggies!). Many people also just find them a lot of work to look after, which is especially annoying when their usage is often only seasonal at best.

But, what if you’re already lumbered with a pool and are trying to make the best of the situation? Maybe it came with your property, or hindsight has kicked in after you’ve shelled out thousands to install something you almost never use…. What then?

Some simply drain their pool of water and leave it at that. Although that is an option, it isn’t a particularly attractive one, and the pool interior will still require periodic sweeping and cleaning if you want to avoid raised eyebrows from your mother-in-law and other guests.

Is there anything you can do? Is there a way to use the pool while maintaining aesthetics and perhaps even bringing some other benefits with it?

A couple of days ago I stopped in at the home of Vanessa Fernandes (a former PDC student of Geoff’s) and Justin Sharman on Australia’s Gold Coast – to check out a rumour I’d heard of their swimming pool conversion. It was a fascinating visit!

Permaculture gardens and the pool blend beautifully

You see, about eighteen months ago, after a little contemplation and research, Vanessa and Justin determined to make better use of the big watery pit in their back yard. They decided to turn it into a biologically active fish pond!

The work is still in progress, but is already, in my opinion, a seriously superior version of what they had before. If a pool-to-pond conversion is done well, aesthetics can improve dramatically, and you can also end up with a regular supply of fresh chemical-free fish for the kitchen.

Eating from the pool didn’t seem to be the primary goal for Vanessa and Justin, but rather to create a closed loop biological system that would add beauty and diversity to the rest of their Permaculture system.

How they did it

After draining the pool, they set to cleaning it of contaminants by scrubbing the inside with vinegar and rinsing it clean. This is important or the fish you introduce could die. Before introducing fish, however, plants need to be established, as well as the all-important oxygen-generating algae. Algae forms on its own when allowed, and the best plants to introduce are those you’ll find in natural freshwater environments in your area (lakes, ponds, rivers) as these are best suited for your climate. Justin and Vanessa even introduced a couple of plants that are regarded as ‘pests’ by many government authorities – like salvinia, a fast spreading floating fern. Rather than a pest, the plant serves a purpose here as chicken feed, and its characteristic of spreading fast just means the chickens have a good supply of it!

Another plant introduced is azola – which is very high in nitrogen due to its special relationship with a nitrogen-fixing cyanobacterium. This makes it an exceptionally good mulch (azolla is said to increase rice yields significantly – "as much as 158 percent per year"). Of course, they also introduced plants that are great for human consumption – like kangkong, water chestnut and watercress.

The upside down crate in the water acts as a chicken self-rescue platform, in case
one chicken pushes another in (out of spite), and the hapless victim needs a way back out

At the moment the pool supports about a dozen silver perch ("plate sized", Justin said. "About 4-8 kilos of fish weight"). These are native to the region. The fry you can see below are munching on bread we tossed in to tempt the bigger guys that like to hang out in deeper water. I was hoping they might come up an impromptu photo shoot. The adults did make a showing, but they must be seriously camera shy, as they’d only lunge at the bread and disappear before my trigger finger had a chance to move at all. As we had another pressing engagement, I didn’t spend more than a few minutes on this, so forgive me for not supplying a picture of the final ‘product’. I guess it’s yet another fish-that-got-away story….

Baby fish snack on bread that was thrown in to attract the larger fish further down

At the moment the pool is essentially a closed loop biological system. The plants feed off the nutrients supplied by fish and bird droppings, the fish feed off the plants and insect larvae (like dragonflies, etc.), and the algae regulates the CO2/oxygen levels. Zooplankton and mollusks (snails) feed on the algae, the crustaceans (shrimps) feed on the zooplankton, and the fish feed on the mollusks and the crustaceans.

Oh, speaking about snails, if anyone spotted the blue hoses at top and thought I really should have pulled them out before taking any pictures, let it be known that I was going to do just that, but got stopped in my tracks. These hoses also serve a purpose – snails cling to the outside, and also live inside the hose, and it’s from these hoses that the fish like to feed.

As mentioned, algae is very important for the health of the pool – but you can have too much of a good thing. Algae blooms are to be avoided as they can suffocate life in the pool. A balanced algae population can be regulated in three ways: 1) reducing nutrient input (i.e. harvest some fish), 2) reducing light (i.e. add a translucent shade, or a living vine, over part of the pool), or 3) simply scoop some algae out if you get desperate and use it for mulch or compost.

The biggest thing stopping a decent increase in the fish population is oxygen. To regularly eat from the pool, Vanessa and Justin would need to incorporate a water filter/oxygenation system – which is something they’re looking at doing next. As you can see from the pictures, the water in this particular pond is rather ‘natural’. A biological filter would make the water clearer – so, if you wanted, it could still retain the pool’s original purpose (swimming!). Increased oxygenation also tends to keep algae from getting out of hand.

A bio-filter doesn’t need to be too complicated or expensive. Water could be pumped out of the pool and through a gravel trench, and then back into the pool (a solar pump could be utilised). As the water passes through the gravel it gets filtered/cleansed (by the algae that will develop there) and oxygenated. Reeds growing on the gravel aid in making the biological filter itself a closed system.

As well as the general aesthetic and the potential for increased food security and health, pools like these also contribute to the health of the garden in general as they attract a greater diversity of wildlife. Vanessa and Justin now have regular visits from predatory creatures, including white-faced herons and even the australasian bittern, a threatened species.

Essentially, a pool like this is a great example of the very essence of Permaculture – working with natural synergies, and finding ways to make them work for ourselves and the environment. Where modern agribusiness concentrates on chemistry, Permaculturists deal in biology. Instead of reductionist science, which would take just one element and pull it apart to its base chemical ingredients before we look up thinking we understand something, this kind of management takes a broader view.

This reminds me of an excellent passage that brings this thought home well:

Working with living creatures, both plant and animal, is what makes agriculture different from any other production enterprise. Even though a product is produced, in farming the process is anything but industrial. It is biological. We are dealing with a vital, living system rather than an inert manufacturing process. The skills required to manage a biological system are similar to those of the conductor of an orchestra. The musicians are all very good at what they do individually. The role of the conductor is not to play each instrument but rather to nurture the union of the disparate parts. The conductor coordinates each musician’s effort with those of all the others and combines them in a harmonious whole.

Agriculture cannot be an industrial process any more than music can be. It must be understood differently from stamping this metal into shape or mixing these chemicals and reagents to create that compound. The major workers – the soil microorganisms, the fungi, the mineral particles, the sun, the air, the water – are all parts of a system, and it is not just the employment of any one of them but the coordination of the whole that achieves success. – Eliot Coleman, The New Organic Grower, p.3, 4.

Justin and Vanessa’s back yard is not only a productive permaculture garden, but also an extremely beautiful wildlife habitat. I think my camera and I will have to stop by again sometime….


Justin gave me a few resources that they found useful for their pool:



  1. Way to go guys! Nice to hear your doing so well and keep up the good work. We’ll have to come see your place next time we’re in OZ.

  2. What a good job you permi’s surprise me every day – and it looks more in-tune with the environment than a blue sparkling pool! Just have to add gravel grow beds to filter the water – the fish waste can feed vegetables, check the forum at

  3. Awesome work!

    This is the future of suburbia and the urban houses…

    It is these kind of efforts that will lead the way forward.. keep up the great work and please document and share your experiences with us all.


  4. I have had my pool/pond converted 8 mths neighbors now complain about mossies, which are a problem .. how do you control mossies Ihave some plants floating salvinia and about 17 young silver perch 11 fingerlings 6 slightly larger.. water quality looks good.

    1. Look up Ku ring gai Pool to pond. Peter Clarke. Mozzies that bite do not breed in deep water only in shallow water such as pots with bases, spare tyers forgotten. Other things where shallow water collects Your neighbours may want to look to see if they have any of these attractive things in their space. If you have fish there wouldn’t be any coming from your pond anyway except the odd getaways but they don’t bight. Our pond is beautiful and we can swim in it as well with the fish and it is a blessing as it cleans itself and is much cleaner than a chemical pool. Good Luck

  5. Gday bill sorry it has taken so long to reply but I have not had my eyes on the link for a while and life takes over sometime.
    I can also recommend that you plant out you step area with a range of different plants, reeds are great and anything like persicarius kang kong etc etc diversity is the key.
    I source my plants from healthy systems in my local area, when you do this you are also importing lots of micro flora and fauna. This will eventually attract dragon damsel and may fly’s as well as a host of other beneficial insects, the reeds are important as these insects spend up to a year in the water in the nymph stage, the nymph will provide excellent mozzie control for you as larvae is a primary food source. Some times the silver perch can be a bit lazy about surface feeding and the mozzies use the shape of the leaves to cradle their own brood, give the salvinia a good shake up to disturb this and like Geoff says that will give access of larvae to your fish. I also have other little guppy style fish which breed like flies and munch on the larvae and any excess food on the surface; the silver perch do not seem to eat them at all. The dragon fly nymph then climb up the reeds to morph into an excellent beneficial air force that will patrol your garden and pool.
    Bidyanus bidyanus start with a basic diet of zoo and phytoplankton’s mixed with molluscs then move onto green diet plants algae as they grow .It’s important to purge your fish for a week or so in a smaller tank of clean water with a saline solution about 5% this will make the fish a lot tastier. The primary industry website in nsw has excellent research on all this and they have a great research station in Grafton.
    Best wishes to all

  6. Wonderful presentation! There is one thing I like to hear.
    Before you converted your pool into this beautiful permaculture garden fish pond, did you put some gravel/ sand onto the pool floor to make its bottom shallower for kid’s saftey? With many thanks, Yan

  7. Yan Park’s question is a good one…after the pool has been scrubbed, how was the base prepared. Pools can be deep. Sand ? gravel ? Mud ? Were structures added on which reeds, other plants could grow in containers ? Why was the existing pump abandoned – is water circulation unnecessary or would the algae clog the filtration system ?

  8. Very inspiring. I would like to do a similar conversion and wonder if I could visit this site and get some guidance.

  9. Great project. Well done. Although salvinia and azola are useful for feeding your chickens, they are declared invasive weeds and should be replaced with native, non-invasive weeds. The lovely herons and bitterns that are visiting your pond will transport salvinia to rivers, creeks and other water bodies around the Gold Coast. Unfortunately, the weeds we plant in our backyards never stay there. There are some great websites showing the wide range of native aquatic plants suitable for the Gold Coast. cheers!

  10. Absolutly brilliant!Loved all the fantastic info. We are half way through a pool to pond conversion. The pond has few plants as of yet but plenty of algae and I think is almost ready to add fish I still need to do some research on filtration. We have dragonfly nymphs and water scorpions that have made themselves at home, so far we haven’t had a problem with mozzies although they like other sources of water on our property like underpots etc. I have been working on a food forest and Land for Wildlife project on my 2 1/2 acre property and the very helpful Land for Wildlife fellow Stuart Mutzig forwarded this link to me to help with my goal. If anyone of like mind is interested in coming to have a looksee and exchange ideas you are more than welcome. I live at Caboolture and you can email me on [email protected].
    Once again great job guys!

  11. very noice! makes me wish i had a pool to convert. Friend of mine years ago did a natural pond with a creekbed and small filtration pond at the top and planted the whole area out with tropical fruit trees- not bad for suburban Perth WA..
    We are starting small with an aka-aquaponics set-up but I came across this site which made me think about combining the two ideas yet again. I can think of nothing better than to lounge around in a pool after a hard days work in the vege patch!

  12. can any sort of conversion be done without changing the water… I am in victoria, with strict water pool quickly goes green and grows mosquito wrigglers if i ignore it over the winter..I would ultimately like to keep fish in it even if it takes a couple of years to achive the water quality..thanks redsue mt matha vic.

  13. I would love to have a natural swimming pool with fish and reeds and so on and got excited by the natural pools site. However, my local pool shop told me that in our area (Byron Shire, NSW) a number of people have tried it and have failed because of the heat and rainfall here. Does anyone have a success story for a natural pool that is swimmable in this subtropical climate?

  14. Hi All,

    I am a commercial gardener in Adelaide and have a client who is interested in converting their pool to a pond with simple goldfish and similarly supported species.

    Does anyone have a step by step guide that can walk you through the process of conversion? please email me at [email protected]

    thanks Adam

  15. Hi again,
    This is a reply for Sue Branson in Vic. My pool kept going green so I just allowed it to sit for a while. Maybe the pool shop could check a sample of your water to see if there are any chemicals left if you are concerned.My pool had a cover over it and wrigglers only started when I removed the cover. Not too long after that there were Back swimmers and dragon fly larvae and that lead me think it might be safe to try some small fish in there to keep the mozzie wrigglers down. They thrived and bred very quickly. So after that I added crayfish and Silver perch and they are all growing well. Hope that helps. Cheers.

  16. This is really cool!

    Surprised you don’t eat the fish you raise. Sure you’ve got friends who wouldn’t mind a spot of fishing over a beer or two.

    Any frogs in there?

    1. Frogs will be in paradise. All wildlife . birds and the list goes on. No fishing :-)
      That would be damaging to the eco environment.

  17. I am in California and would like to convert my pool into a fish farm pond. do you all know of an organization I can contact in the USA?

    1. i am in louisiana and have a ecological balanced swimming pool for over 10 years. it is 12 x 31 feet and i love it. there are bull frogs snails and around 150 beautiful comet fancy tail and straight tail fish started from 5 3 “fedder goldfish from petsmart. i have pink lotus and a floting willow tree among other plants iris and such.Huge bullfrogs . this is a no maintaince no pump no filter ecosystem. Do you think i could add native crayfish and other type of native fish without harming my system. i have lost only 2 or three fish over a 10 year period.How great is this!!!

      1. Wow, your pool pond sounds like it’s doing great. I wonder how this would work in Indiana? Maybe I’d have to aerate it through the winter.

  18. Gday, I’m hoping to turn our 3.6 diameter x 1.2 deep poly pool into a red claw / silver perch set up. might even try barra. can anyone tell me about the filtering side of things to do this ? thx chizo

  19. It seems great. I don’t like to have a pool fence. If I convert my pool into one like you have, is it OK without a pool fence? Thanks.

  20. If you want to go small on these types of set ups then go to the aquaponics forum for advice or better still grab one of Murry Hallams videos he is very experienced the smaller the system the more management required.(video available on this site)
    If you are going big then Nick Romanowski has some excellent aquaculture resources and would be considered the “guru” of that type of extensive Aqua culture.Converting my pool has been the best experience imaginable,it produces twice its surface area in rich compost materials supports many species of edible plants host many beneficial bugs and insects.I feed my chickens about 200grams per week of small native fish which supplements their protein,and I now have visibility to the bottom of the pool almost clear water.I still have 4 large Silver perch in the pool about 400-600 grams each.If I wished I could increase the fish stocks by adding a small pump and aerator and fertilizing the pool to create more food for them to eat.At the moment it suits me to keep it as is.I will post an update at the end of January after I have made some more observations on the pro and con of the different things I have tried.
    Thanks everyone for their interest,I would like to answer more questions but I believe that if you are going to run a system like this and keep it healthy there is no easy one thing fits all,it’s best to really research it so when you are observing your system you are making judgements based on the science.Francoise one of the earlier posters came over to see the system,anyone who is in my area is more than welcome to do the same please give me some notice before dropping around.I am most easily contacted through face book.

  21. This question is for Luisa, I was wondering what exactly do you mean by Crayfish? or do you simply mean Yabbies??

    Just very interested.


  22. Wow an amazing article and what a great idea. Wish I would have done this with the aquaponics garden we had set up in our old home. We had a broken down pool but just kept it empty as to not waste water. Really wish we would have read this 3 years ago.

  23. I was wondering if a friend and I could visit Justin and Vanessa’s project sometime in the future as I am determined to convert my pool to a biologically sustainable fishpond. I live at Verrierdale on the Sunshine Coast which is near Eumundi. I have 5 acres which I want to get much more productive foodwise.

    Please pass my message to J and V for their approval or not.

    Rick Hill

    1. Hi Rick, I live in Doonan, am wondering how your conversion went? I’d be really interested to chat with you if you wouldn’t mind? Thanks, Nelly :)

  24. HI, just started on converting pool to pond, problem is it has gone slime green, Have plenty of plants which to be doing well but the water seems to be smelly also is this normal ,should i pump out and start again have no filter system in place but would like to start on that any help would be greatly appreciated on where to find info on gravel filter system
    thanking you

  25. We are just starting our pool conversion. It doesn’t take long for the boatman insect to come into the pool, at that stage I believe it’s ok to start introducing fish? We did an experiment with local caught carp to see if it would hold fish safely and yes it worked – they are gone to compost now – but it worked well!

    Could anyone answer this? Can a normal pool filter (sand) work as the filter system for a conversion? I figured if it’s already installed and in good working order why not use it? Of course, it’d be better to convert that to solar, but for the short term it might work??


  26. Hi, I am in process of converting our fibreglass swim pool into a fish pond. Filter off, water green have alzora floating on top and have bought many Aust native water plants to grow in the pond, but I dont know for 1 how do I anchor the plants to the pond floor in pots filled with what?
    2. do I plant them in sand, rock or peat or soil?
    3. Is it ok to still vacuum the bottom to remove all the leaf debris that falls in?
    4. How do you disguise the pots in the pool?

    1. I began converting my pool around March 2014 with the help of a friend. She brought me lots of plants and tubs which we raised and placed on the steps. I live in Maroochydore on the Sunshine Coast. I went to the pet shop and purchased some fish there to get rid of mosquitos and was to put in some silver perch however just watching the fish and seeing their offspring swimming around happily gives me please and they seem happy enough. I grow lots organically in the garden and have 3 compost bins and a number of worm boxes. I feed the fish worms and they love them! I was told to oxygenate the pool 5 am is the best time to put the waterfall on. A female friend changed the pipeline from the roof so now all the rain on that side of the house fills the pool which I then put into my watering cans to water the garden, thus saving water bills!
      That’s about it. I was think of buying some azolla to feed the fish. Any ideas would be welcome

  27. I too have had enough of my pool & last November started the conversion by turning off the filtration. Luckily I had a chlorine pool so just needed to wait for the chemicals to dissipate.
    Every nursery I spoke to with the exception of one was very negative & assured me it couldn’t be done without spending $1000s.& it would never work. Well just 8 months in & my pond is thriving. I have a closed system relying on just plants & fish, & the water is crystal clear. I thought it would take at least 18 mths to get to this stage.
    To answer some of Carol’s questions I used tubs with handles so I can hook & move them around the pond & also pull them out for repotting(just plastic industrial strength buckets)they are big enough to sink & remain fixed without moving.The potting mix used is just good quality garden loam with a packet of pellet fertiliser in the bottom & Mary River course gravel on top. This is what the local nursery uses. I do not vacume anything from the bottom & have removed my pump completely. Still occasionally remove some larger debris but if you have enough plant cover the water quality will not be effected. Remember you will be able to divide those plants you already have so there will be a time when you don’t have to buy any more, also check your local waterways. I haven’t disguised the pots but if you use green they tend to camouflage pretty well. Good luck.

  28. Not sure what state you are all in, but my neighbours complained about my pool conversion to pond and the council have demanded i drain it to 300ml, due to mosquito and ‘pathogen’ health risk.!
    The pond water is healthy, doesn’t not smell, attract mossies; is full of healthy fish and frogs and plants and also filtered through a portable pond fountain/filter.. Can they do this?
    It is also fully fenced and passed the invasive pool testing..after heightened fences, put up signs and added a lock to it.. The council lady suggested i would be up on a possible man slaughter charge if i drain it immediately and gave me a week to do it!! A little over the top, i don’t have any kids around here or in my garden at all, its also totally fenced.. advice if anyone can would be appreciated.. thanks

    1. Susan, that seems extreme, unsure what state you are in but Kuringah Council in Sydney is asking people to turn their unsused pools into ponds and there is even info on their website on how to do this. Maybe your neighbour has a friend on council trying scare tactics, I would get further advice from someone higher that the local councuil you are dealing with if you are in NSW.

  29. Fit a waterproof yellow light above the water to attract insects at night.insects fall in water which is perfect food for fish.I’m from port Elizabeth south Africa and looking to convert my 50 000L pool

  30. Does anyone know if anyone in the US has done this successfully? I would love to convert my pool, and could use all the help I can get.

  31. Awesome story. I really want to do this at my father’s house because the pool is litarally never used, not like it was when I was growing up, and it is just a money sucking pit. Trying to talk the old man into this hasn’t been easy either. There’s the financial aspect of conversion, upkeep, legality here in Southern California, etc… The pool is an eyesore and a headache. I thought draining and turning it into an underground greenhouse but that went over like a lead balloon. I like the pond ecosystem idea with the ability to grow our own fish for consumption. I am hoping we can get something like this accomplished here in the near future. Thanks for sharing.

    1. Hey People I am in Brisbane Australia and i want to build a organic pool /Pond in our backyard does any body knows if i can put fish in it if i want to swim in it during our hot summer days and a other question that i have were can i buy water plants in the Brisbane area Kind regards Remco

  32. Thanks all, I have a 38,000 litre swimming pool , that I am sick of spending $$$$$ on, The Kuringai Council info is fantastic, I am also looking at adding a gravel bed external filter with plants and a water fall effect for extra oxygenation (all home made from recycled IBC) does any one have a resource for info on suitable gravel, the gravel from our quarry is highly acidic ?
    Thanks in advance

  33. a question:
    there is a swimming pool in the house i’m renting and i’d love to convert it into a pond, but would this ruin the pool structure? i need to know because one day i’ll move somewhere else and though i can take the fish etc with me i couldn’t leave a destroyed pool behind…

  34. Hi! I’m currently working on a pool to pond project in Fremantle WA. It’s 55,000L and I left it to turn green and when there were water boatmen skaters etc I put in a few small fish. Have now got about 40 koi 30 silver perch and 20 marron.Have lost a few fish to a big heron that comes to fish all night on the full moon so I have netted the pool until I get a motion sensor sprinkler that I found out to be the answer on another forum
    Planting lots of Taro/ Papyrus/ water chestnuts/ watercress/ moneywort/pennywort/vallis/ water mint/water spinach etc in the pond but also pumping thru growbeds with different herbs and veg.
    Found a great book at the library called Edible Water gardens by Nick Romanowski. Great project, so exciting!!!? So many evolving ideas thru reading these threads and the Ku-ring gai shire info – so much better than adding chlorine and vacuuming ad naseum with nothing to see!! Anyone in the Perth area doing similar? Would like to meet up with other pool to ponders around the area?

    1. Hi Adrian,
      I would love to catch up. I found your comment very helpful ( resources listed and city). We currently have a salt water pool around 30 K L. in Darlington Perth. Just starting the research. Will check out yourreferences.

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Articles

Back to top button