Most kids love to have unlimited access to a pool; they would be in it for hours every day if they could. However, parents are not always the same. As you get older, it takes more effort to go swimming in the backyard pool and you probably have many other things you would like to do instead. So now that the kids have left home or are more interested in their hairstyles than swimming, is that backyard pool gathering metaphorical dust? Why not convert it into something else? Something that could become a very interesting hobby. What?
A fish pond! This is not only ecologically sustainable, but you will have a great supply of fresh fish on hand for dinner. We tend to think of a fish pond as something about knee high holding rarely seen fish only a few centimetres long. If your swimming pool was converted to a fish pond there would be no reason not to grow fish to eat in it. It is deep and big enough that many fish would thrive.
Fish and chemicals don’t mix
Of course, you can’t just purchase a few fingerlings and throw them into the pool without some kind of preparation. The chemicals in swimming pool water would kill them. So it is not only imperative to drain the pool, but to scrub all the inside of it with a solution of vinegar so that not one tiny bit of chemical remains. Once that is done you can add plants and the kind of algae that generates oxygen. This will make the environment fish friendly. Some of the plants will need to have wide leaves so the fish can hide under them from feathered predators.
Choose the natives
Choose fish that are native to your region or known to be adaptable, as well as tasty. One pool is said to support about 12 plate sized silver perch with a few fingerlings thrown in. So how does this actually work? Every part of it sustains another part. The nutrients provided by the fish and bird droppings feed the plants and the plants, along with insect larvae, feed the fish. The algae regulates the oxygen/CO2 levels and provides mulch for the garden when it starts to overtake things. This avoids algae blooms that are likely ruin everything.
The advantages of oxygen
An oxygen system is optional but has several advantages. More oxygen means the fish will grow bigger. The pond water will become clearer rather than being a greenish colour so aesthetics are restored and you can actually still swim in it.
A big advantage of having a big fish pool is that it will attract other wildlife to your backyard such as birds that are often not seen in cities or suburbs because of their need for water-based food.