my first post on Permies and I'm not even sure where it should go.........
I have a question about fish.... specifically what varieties are best suited to aquaponics? Also is it worth trying to breed/grow edible fish types in a small suburban system? If so, which breeds are best and how long do they take to get to edible size?
Sorry if there's too many questions in one paragraph.
To complicate it more, do you even want fish or would crayfish or some other aquatic animal do a better job?
Some of it depends on what you like to eat, and whether your focus is more on using the fertilizer from the fish for growing plants vs. using the plants to filter the water so you can grow tasty fish. If you want an equal balance - great fish plus great vegetables that becomes a little more tricky.
For getting the most fertilizer value, you can't beat goldfish. Known in the aquarium world as "messy fish" they'll put more nitrogen in the water than just about anything, and they're cheap to buy if you use plain old feeders. Or for profit you can buy small koi and then sell them in the spring when people want to stock their ponds. As the size goes up so does the price on Koi, phenomenally!
Other than that, it depends on your system. Trout like cool, running water - hard to do if the summers get hot where you are. Many fish give off hormones that limit their growth in overcrowded situations, and I've never gotten a clear answer whether the plants in an aquaponics system would remove them or not. I know bluegill get stunted when they're too crowded.
If I were doing it, I may go with crayfish. There's a kind called marmorkreb that clones itself and doesn't eat its own young (unlike many other kinds of crayfish). You can feed them plant waste, they tolerate a range of water temperatures and even some pollution if your system has kinks that need to be worked out. I had some for awhile and they're fascinating - the mother carries the eggs on her tail and the young when they hatch for awhile then they go off to hiding places and grow. Some crayfish go through a nymph phase but marmorkrebs start out as tiny crayfish. Without territorial males fighting, marmorkrebs are amazingly peaceful.
If your focus is on fish to eat, then it would be tilapia they will even eat algae that grows in the water and bluegrill for colder water.
If you want a system that is not too picky, then carps including goldfish/catfish/koi, they can survive in just about mud alone.
To help assist you better here are a few question that would help alot:
Are you going to heat the water in the winter, what is your summer temp.
Do you plan on oxygenating the water.
Do you plan on using fish food or will the fish have to forage for itself.
How big is your system going to be.
Are you using a pond or just some buckets.
What does you budget looks like for your aquaponics.
Tilapia seem to be one of the most common type of fish used in aquaponics. They're omnivores so they'll eat almost anything you give them, including mosquito larva and algae. If you like to eat fish they taste pretty good too.
However, if you're starting your first aquaponics garden expect to make mistakes that could mean the lives of your fish. From personal experience I would recommend using the cheap 25 cent feeder goldfish you find in pet shops until you're more comfortable with your system.
I have been using Tllapia ( O Mossambicus) in my backyard aquaponic system for a few years. Very hardy. Breed well. If you just need them to provide nutrient (and are not that anxious about getting them to grow big quickly) they can survive with duckweed only. Watch the oxygen levels, especially in warmer weather.