maggie - Absolutely you can do it. Remember it's just a concrete pond. There are hundreds of koi ponds both in ground and sat elevated on the pavers of lanais.

Does anyone have experience doing this?

Yes it can be done and it doesn't even require draining the pool completely. What you may want to look into is Aquaponics. There is a huge forum at Backyard Aquaponics
http://backyardaquaponics.com/forum/portal.php
If your pool already has a pump and sand filter and you are only going to have a few fish, you will probably only need to do a small amount of filter upgrade (perhaps like a waterfall with lots of lava rock in it.) Biggest challenge would be how to do plants in such a pool.
Hope to see you at backyard aquaponics.

Oh, and I expect koi will survive there though I always just tell people to get some goldfish instead of spending lots of money on koi, at least to start out anyway. Of course, you might even be interested in growing food fish and food plants if you get too into the idea.

Here is a link that might be useful: www.TCLynx.com

Hi
A SP would make an ideal Koi pond. Koi are very large fish and most people cram them into shallow way too small ponds . You could also keep tropical fish.
There are a bunch of websites on doing this. I've always wondered if there is a problem with city ordinances??
gary

I know if I had a swimming pool, it would have been converted to a koi pond long ago. The screened area should make it even easier to maintain since you won't have to deal with leaves.

Gary is absolutely right that most people who keep koi(me included) don't have anywhere near a large enough area to show off their beauty.

We checked into this at our previous house.
Our pool need to be resided.
We went over to a pond store over in Tampa
and the only major problem they could see was,
the light blue color of the pool would attract algae.
If we were to do it, have the pool company marside(?) in black.
I always thought that would be cool to walk
out the diving board to feed the fish..........cheryl

Garden Web has another forum called "Ponds and Aquatic Plants" Go over there and do a search as there is alot of info even on swimming pools to ponds.

Now my only major concern is whether it would be easy to convert back to a swimming pool if and when the day ever comes when I would want to sell this house. I remember my gardens up north being a relatively negative selling point to many buyers. Does anyone know of someone who has tried to revert their pond back to a pool?

Hi Maggie,
I had a friend that converted her pool into a fish pond. She just let the water get old and then she put goldfish in it. She put some plants around and in the steps going down to the bottom of the pool. The fish multiply quickly.Annette then sold her house to Gwyn,also a friend of mine. Gwyn gave me all
the fish because she wanted to turn the pool back to swimming condition. It was a mess. after the water was drained the walls had to be water pressure. She also had it
resurface,patched and tiles replace. The filter system service. After allot of work,I helped,professional help.
It was costly but fixable. Then they moved away.
Oh the pool was deep enough that the blue herons never got any fish. I got over sixty good size gold fish from them
only to be killed by the blue heron.
Felix

There are several different ways you could go at it. If you want to keep it easy to convert back to "swimming pool" and keep the cost down for both factors, here are some suggestions.

Leave the color as is, the blue isn't that big a problem with algae and a black swimming pool might not be as easy to sell. Some shade for the pool will help against the algae as well as would having it coated in black.

Let the water age to get rid of the chlorine. (What source of water do you have for re-filling if you were to need to do any water changes? If you have city water with chloramine you might need to look into some water conditioner.)

What is your existing pool pump/equipment? In some arrangements, you could simply continue using the existing pump/filter. Or you could shut down and drain (like for winter storage the pump and sand filter, if you do this properly, the equipment can be hooked back up when wanted for a pool again.)

Then you can get a submersible pond pump and a bio falls basin. Put the pump in the pool and hook up to the bio-falls basin sitting on the edge of the pool and you are set to go for small numbers of fish. Add some aquatic plants (make sure they are in large plant baskets with gravel, no dirt.) Place potted plants around the falls tub to dress it up a bit and away you go. Now this might not turn your swimming pool into a perfect ornamental pond but it is the cheap way to do it. Make sure to choose an energy efficient pump as you will probably be running it 24/7. In warm water you need to keep it flowing or the fish can run out of O2. It is best to start out with smaller numbers of smaller fish and keep the feeding light until the system has stabilized.

Now if you want to make it really fancy, it will of course get more complex and costly. If you want large or lots of fish, then you will definitely need to learn more about Aquaponics, bio filtration, fish keeping etc.

Here is a link that might be useful: www.TCLynx.com

Thanks for all the information from everyone.

Right now I have a DE filter - my friend who is also interested in this topic has a paper type filter. I already have a raised spa that waterfalls into the pool.

I think this is going to take a lot of research but am excited to see that it is really quite doable.

Are you wanting to keep the spa usable or convert the whole thing? (To keep the spa usable with chemicals might be tricky to isolate the two from each other.)

A spa that waterfalls into the main pool could make a perfect bio falls since it probably also has bubbles though it might be difficult to fill with gravel without damaging the surfaces.

Have fun in your research.

Here is a link that might be useful: www.TCLynx.com