There are a wide variety of fish from which to choose for your Aquaponics System. The most important thing to keep in mind is to use freshwater fish. You might be wondering which fresh water fish to raise? To figure this out, start by deciding whether you want to grow fish for show or for food. If you are interested in growing edible fish, Tilapia are most commonly used in aquaponics because they are a tasty, fast-growing fish that have low oxygen requirements and aren’t very fussy about their aquatic environment. Tilapia are generally purchased at fingerling size (12-15cm) and take 8 – 11 months to reach “plate” size (approximately 20-24cm and 750g). Many other edible fish can be raised as well, including trout, catfish, and perch. Don’t be afraid to try other species. Just be sure that when you create your fish environment, you plan for optimal water temperature, sociability, and diet for which ever species you have chosen.
A Red Breast Tilapia (Tilapia Rendalli) - Arguably the best fish for an aquaponics system, and certainly the best tasting fish. The red breast tilapia is predominantly herbivorous and will eat lettuce, duckweed, aquatic plants and even kikuyu grass. Duckweed has the highest protein content, so best suited for fast growth. It is recommended that you also supplement their diet with worms (start a worm farm) and other insects that you may catch in your garden (crickets, flying ants, grasshoppers, snails).
Below are some photos of our Tilapia Rendalli juveniles (fingerlings). A mere 3 weeks old:
Other Tilapia species indigenous to South Africa is the Mozambican Tilapia (Tilapia Mossambicus). Your tilapia species require water temperatures above 22 degrees centigrade. Anything below that, their metabolism slows down and they stop eating. As water temperature gets close to 10 degrees Cenntigrade, your fish will start dying.
If you wish to keep your fish as pets instead of food, then we suggest you grow Koi, they can get quite tame and eat out of your hands.
Other fish you may consider for your Aquaponic system here in South Africa are:
- Trout (cold water tolerant)
- African Catfish
After you have chosen your species, you will have to decide how many fish to put into your tank. The safest stocking density is 30 to 40 Killogram of fish per cubic metre of water. With African catfish you can stock up to 700Kg per cubic metre of water !!!!
Remember to keep the water in your tanks crystal clear, keep PH levels between 6.8 and 7.2 and do not allow for ammonia levels to get too high. Keep the water circulating and clean. Do not ovefeed your fish, feed only what they can consume in 5-10 mins.