The genus Acarichthys is monotypic, meaning it has only one species: Acarichthys heckelii. The genus was founded in 1912 by Carl H. Eigenmann.
This species occurs in South America. They occur over a widely distributed area. They inhabit the larger rivers of Peru, Colombia, Guyana and Brazil. In particular, the Amazon, Rio Putumayo, Rio Trombetas, Rio Negro, Rio Xingu, Tocantins, Rio Capim, Rio Branco and Rio Essequibo.