Species group: Catfish
Other common names: Lungfish
Scientific name: Heterobranchus bidorsalis
The African Catfish is a native to the Nile River, Niger River, and the Gambia River of East, North, Central and West Africa. They are caught in the wild, and being air-breathing fish are particularly suitable for aquaculture. Heterobranchus bidorsalis is the most commonly reared catfish species in Southern Nigeria.
African catfish are demersal (live and feed near the bottom of rivers) and inhabit freshwater. They are detritivores and eat a mix of decaying plant and animal matter on the riverbed. However, as they are air-breathing, in aquaculture systems they are typically fed floating pellets made from blends of high-protein vegetable matter.
They are typically marketable at 6 months of age when they are between 600g and 1kg in weight. Current experiments are aimed at growing catfish and nile tilapia together in the same aquaculture system.
Though African Catfish is the common name for this fish, it is also the common name for the other commonly-farmed catfish on the African continent, Clarias gariepinus (which is the only pan-African species of catfish and is the most extensively farmed in Southern Africa) and Clarias anguillaris.
In West Africa, the catfish are often raised on relatively small scale near where they are sold and they are always sold alive. Indeed, it is traditional in Nigeria to sell them as what is known as 'point-and-kill' where the fish is chosen, dispatched on the spot and then made into the classic local pepper soup with plenty of hot Scotch Bonnet chillies.
It is characterized by its numerous, long, barbules and sleek, eel-like profile (particularly when young).The belly is typically white to cream, however the upper surface of the fish varies markedly in colour from light grey through olive green to dark brown and may be spotted. Ruddy-hued fish are also known. In profile, the body is narrow and eel-like in profile, particularly when young. Viewed from above, they are broad and almost rectangular in appearance, narrowing towards the tail. The head is wide-mouthed, shaped like an oval and possesses a single rectangular dorsum. The snout is rounded, the eyes are arranged laterally and the postorbital bones are completely united. The pectoral spine is smooth and the fish has a long dorsal fin that may possess up to 46 soft rays. The anal fin typically has between 50 and 58 soft rays. Overall the fish have 62 vertebrae. Lateral fins are long and sited just behind the gills. These have hollow spine set just behind them that can be extended as a deterrent to prey. Catfish are unusual amongst fish species in that they are 'naked' and possess no scales. African Catfish are also characterized by their barbels, of which there are four pairs, with the maxillary barbels being the longest (these can be 1/3 as long as the fish itself).
Weight: Maximum caught, 32kg (1.5m in length). Typically sold at 500g to 1kg (25cm in length). Fish for breeding are typically between 400g and 1kg in weight.
African Catfish are typically sluggish fish that conserve their energy. If handled gently they are calm and can be affectionate. But they do have spines, which they project if harassed or threatened. These are very painful of they break the skin.
Typical stocking rates for the African Catfish is between 2 and 10 fingerlings per square meter. They are either kept in large earth-banked ponds fed by natural river waters. Where there are no rivers, they are kept in large concrete tanks, fed by water derived from boreholes. Spent water, which is high in nitrogen is used as liquid and fertilizer for crops.
In the wild, African Catfish are detritivores and feed on semi-decaying organic matter on the river bed. In aquaculture systems, they are typically fed surface pellets made from fish meal that are rich in arginine, methionine and lysine, In Africa, however, this is expensive and the catfish are more typically fed a range of foods that range from duck droppings (often ducks are allowed to swim in the same pens) to pellets made from groundnut cake and soyabean cake.
Catfish are typically healthy fish, though they do suffer from skin infections and gill infections. As will all aquaculture systems, the ponds and tanks need to be scrupulously sterilized each time the fish are harvested or moved on. Water derived from boreholes is preferred to using river water as it reduces the likelihood of infection. As with most other animals in Africa, predation and infection by insects can be a major problem and all tanks should be covered with mosquito netting. Though they are air-breathers, the African Catfish still requires some movement of water in their tanks to maintain gill health and to reduce stress.
It is also particularly resistant to water pollution, particularly nitrates, which makes it particularly suitable for intensive, but relatively small-scale rearing; though they an also be reared on a large scale. They are typically housed in concrete tanks, fed water by local boreholes.
For their survival, water temperature must be between 22ºC and 28ºC.
food fish, market, healthy appetites, professional breeder
aquarium, smelly business, muddy water, tank life
veracious appetite, harshest waters, eel, good quality flake, bloodworms, catfish pellets