Heterotis

Heterotis is a genus of freshwater fish belonging to the family Osteoglossidae, commonly known as bony-tongues. The genus currently contains only one recognized species, Heterotis niloticus, also known as the African Arowana or Nile Arowana. This large, elongated fish is native to the freshwater systems of Africa, including the Nile River basin, Senegal River basin, and Congo River basin, as well as being introduced to other regions.

Heterotis niloticus is characterized by its long, cylindrical body, a large mouth, and a relatively small eye. Its coloration is typically silvery or bronze, with irregular dark spots along its sides. A distinctive feature is its dorsal fin, which is long and extends along much of the back. They are air-breathers, possessing a suprabranchial organ that allows them to extract oxygen directly from the air, enabling them to survive in oxygen-poor waters.

These fish are opportunistic predators, feeding on a variety of small aquatic animals, including insects, crustaceans, and smaller fish. They are also known to consume plant matter. Heterotis niloticus is a popular food fish in many parts of Africa and is also kept in aquariums, although its large size and predatory nature make it unsuitable for most home aquaria. The species is generally considered to be of Least Concern by the IUCN, though local populations can be affected by habitat degradation and overfishing.