African arowana

The African arowana (Heterotis niloticus) is a species of bonytongue fish that belongs to the subfamily Arapaiminae, making it more closely related to arapaimas than to other arowanas in Osteoglossinae. It has a terminal mouth and is unique among its relatives for feeding extensively on plankton. The fish has a long, streamlined body with large scales, long dorsal and anal fins positioned far back, and a rounded caudal fin. Adults are gray, brown, or bronze, while juveniles often have dark longitudinal bands.

African arowanas possess air-breathing organs on their gills, enabling them to survive in oxygen-depleted water. They also have a suprabranchial organ that helps concentrate planktonic food particles and serves sensory functions. Native to Africa, the species is found in various river basins across the Sahelo-Sudanese region, including the Senegal, Gambia, Niger, Nile, and Congo River systems, as well as Lake Chad and Lake Turkana. It has been introduced to several countries, such as Côte d'Ivoire, Nigeria, Cameroon, Gabon, and Madagascar, though these introductions have sometimes caused ecological damage.

The fish is valued locally as a food source and has been part of the aquarium trade due to its docile nature. It is successfully farmed in its native range because it tolerates crowded conditions and is easy to feed.