Home Aquaponic system, When you are planning to build,
The first question you need ask yourself is in what climate you live. A lot of fish are not that hardy. Strong fish are goldfish and tilapia. Especially blue Tilapia. They live with temperatures around 45F.
The next question you need to ask yourself on which temperature will live my bacteria the best. After answering this you need to know how active the plant and the fish are within current conditions because this will influence your PH which is of utmost importance.
Depending on what sized system and where the fish are going to be (open air, in a greenhouse, in an insulated room off a greenhouse) your heating/cooling requirements are going to vary. Heating water is, of course, cheaper than cooling.
You want to consider the ability to source the fingerlings. Most places can overnight ship the fingerlings to most places, but you’ll want to be sure of that.
Some Legal Issues :
Many tropical or other types of fish are regulated. A quick call to the fish and game department will clear that up for your state/area. Pacu, Tilapia, Gambusia, are all good choices but might have laws specific to your area. Fish like African Catfish is banned in Kerala.
Decide fish depending fish feeds :
Depending on what type of food you want to feed your fish, some fish eat anything (catfish, tilapia, goldfish) and others eat only bugs and other fish (trout, bluegill). It’s easier to keep a fish that eats anything. Growing crickets, mealworms, wingless fruit flies, black soldier fly larvae or whatever you are growing to feed the fish doubles the work. (You can also buy protein pellets for commercial fish food, but this is some gross stuff and I personally wouldn’t want to eat the fish knowing they were eating ground up a rotten cow that was too sick to the butcher, etc).
Raising local Fish :
If you need to have fish that are maintenance-free, consider using the fish that are local to your environment (unless you are faking an environment like in a constant temp greenhouse). So, catfish, bluegill, would be great for most systems because they adapt and can take a pretty wide range of temperatures.
Trout, though native, require cool water with lots of oxygen. The cool water part is the hardest because you need plants that also like cool water, and bacteria growth is very slow in the cool water. For this reason, trout are probably one of the hardest fish.
Both catfish and bluegill are excellent, hardy fish that can be kept together (catfish tend to like the bottoms, bluegill like the tops), but both fish take nearly 2 or 3 times as long to grow to plate size as tilapia. If your goal is to produce fish to eat on a regular basis, you have a growth window to get them from fingerling size to plate size.
If you have to feed the fish for 3 years before you can eat it, it becomes uneconomical. Tilapia can get to plate size within as little as 9 months. Catfish require about 18 months. Bluegill requires about 24 months.
Realize that some fish, like tilapia can easily outbreed your tank size. A tilapia can produce up to 1200 fry every 6 to 8 weeks if the temperatures are right!
To Decorate or To Eat :
Maybe you don’t want to eat the fish at all? Pacu is awesome fish, but KOI or even simple goldfish are great for providing ammonia too. You must be careful that some of the pet store type fish are actually toxic because they are treated with chemicals that don’t hurt the fish but will leach into your system.
An edible fish also needs food at a regular rate and temperatures that are ideal for their metabolism. Decorative fish can go up to a week or two if you had to leave out of town on an emergency. That would weaken both types of fish, but would stunt the growth of edible ones!
Catch Some Native Fish
With the right trapping license, you can make a simple inverted bottle system where fish swim in and cannot exit. Put a few pieces of dog food in several of these traps and put them your local water/lake/ etc the smaller fish will swim in and soon you’ll have several small fish in the bottles. They might have parasites, but this is one way to get native fish. Otherwise, you will need to purchase fingerlings and they can be had for $1 to $5 per fingerling and up to $35 for an adult tilapia, or $1000s for a Koi. Consider this when deciding what works best for you.
Why you Need the Fish ?
If you need small fish to live in the roots of a raft system, without eating the roots, but keeping mosquitos down, fish like the gambusia would be ideal. If you are cleaning an overfilled tank that has no fish in it a few crawfish/shrimp or clams might be good. Consider what purpose the fish are going to serve in your ecosystem. For the most part they are the fertilizer that feeds the plants. If you only consider them as food, you are missing the holistic picture of how the whole system works together.
Bonus Tip :
-Continue to reproduce even at high population densities
-Do not engage in cannibalism at any population density and will fill a tank quickly
-Good market for Tilapia sold as fillets etc.
-Great production of fish per quantity of food given, so they’re quite profitable
-Survive over a significant pH range and in low-average quality water