Gnathocharax

Gnathocharax, is a monospecific genus of freshwater ray-finned fish belonging to the family Acestrorhynchidae, which includes the freshwater barracudas and the biting tetras. The only species in the genus is Gnathocharax steindachneri, also known as the arowana tetra. This fish is found in tropical freshwater habitats in the Orinoco and Amazon basins of South America.

==Taxonomy== Ganthocharax was first proposed as a genus in 1913 by the American zoologist Henry Weed Fowler when he described its only species, G. steindachneri. Fowler gave the type locality of this species as the Igarapé de Candelaria, a tributary of the Rio Madeira and about distant, at 8°45'S, 63°54'W, in Brazil. This taxon was formerly classified in the family Characidae, but is now classified within the subfamily Heterocharacinae, the small biting tetras, of the family Acestrorhynchidae, within the suborder Characoidei of the order Characiformes.