It is the well-known to all cardinal tetra. The first description was made by Schults in 1956, and it was introduced into the hobby by Dr. Herbert Axelrod the same year. It belongs to the Characidae family and lives freely in the Orinoco River. Through the Rio Vaupes, it is found north-northeast in the Rio Negro, in Brazil, up to Western Colombia.

It lives in large schools, in open areas of the jungle that are shaded by vegetation. The impression that dominated until 1984 that it is a fish living in black waters was proven wrong by Geisler and Annibal. Nevertheless, it lives in fairly soft and acidic waters, and high concentrations of calcium (Ca2+) and magnesium (Mg2+) ions cause serious damage to the fish's kidneys with adverse consequences.