Tilapia Rendalli or Red Breasted Tilapia, also referred to as the Rooibors Kurper in South Africa, is one of the most intriguing species of tilapia.
Tilapia Rendalli has 5 to 6 distinct vertical stripes and a red throat and belly. The rest of its body is silvery olive in colour with light brown edges on the scales. The dorsal fin generally has traces of red as does the tail.
Red Breast Tilapia fingerlings are silver in colour.
So why are there claims that it is possibly the best fish for an aquaponics system?
Tilapia Rendalli are omnivorous and will eat worms, insects and algae in the wild. In captivity they can be fed lettuce, grass, water hyacinth, duck weed. One of the first aquaponics farmers in South Africa, Mr Barry Enslin, fed his Rendalli on a diet of lettuce and duckweed only, for over 15 years. Growth rates were not affected and on a par to feeding them with commercial pellets.
As you can imagine, the savings are substantial.. On average, a fish weighing more than 250 grams will consume about 1% of its bodyweight of fish food. In aquaponics, you need to input between 50 to 80 grams of commercial high protein fish food per square meter of plant grow beds in order for the ammonia created to be converted into nitrates (plant nutrients). For a 4 square meter grow bed therefore, you would need to feed around 200 grams of fish food per day to keep your plants and fish happy. At around ZAR15 (USD1) per Kg of commercial fish feed, costs for your aquaponics system start adding up.
By replacing commercial fish feed with greens grown in your aquaponics system, you substantially decrease operating costs. In addition, instead of throwing excess produce into a compost heap, you can now use it to feed your fish.
The one negative about Rendalli is that they prefer warmer water temperatures of between 25⁰C and 28⁰C. Below 12⁰C they start dying.
The other negative, is that they do not grow much above 400-450 grams in captivity, and are of course not as fast growing as the Mossambicus and Niloticus Tilapia species.
Then again, in aquaponics, the main focus should be on going plants and not fish. Aquaponics was not designed to compete with Aquaculture, which sole purpose is to farm fish as fast and as big as possible.
Provided your Tilapia Rendalli are creating the required ammonia in your aquaponics system, which then gets converted to Nitrates by the beneficial bacteria, then its all you need for a successful aquaponics system.
On a final note, though the red breasted Rendalli tilapia do not get too big in captivity, one can still get a nice sized fillet from a 350-450 gram fish. It is possibly the best tasting of all tilapia species. The meat is firm and white when cooked with no overpowering fishy smell or taste. If well marinated, the meat absorbs all the flavours, making for one of the best fish dishes you will ever taste.
For more information on the species, view this article
If you’re not yet a member of the Aquafarmbuddy.com Aquaculture and Aquaponics Community, Click Here to join, its FREE!!