Known only from affluents within the upper rio Tocantins basin draining into the enormous Serra da Mesa hydroelectric reservoir in Goiás state, Brazil. It has been collected from the rios Maranhão, das Almas, Traíras, and Palmerinha/Palmeira(?).

Type locality is ‘Brazil, Goiás, Rio Tocantins basin, Rio das Almas, tributary of left margin of Rio Maranhão, 14˚37′51.2″S, 49˚1′56.6″W’.

Retroculus spp. are unsuitable for the standard community aquarium, and should be maintained in a set-up designed to resemble a flowing river. The substrate should be composed of soft sand mixed with small pebbles if the aim is to breed the fish (see ‘Reproduction’). Rocks, boulders, roots, branches, and aquatic plants can also be added, although the la…