Makunaima is a genus of small characins (family Characidae, the 'tetras') native to Amazon, Orinoco, and Guiana Shield river systems - the atlas records it from Brazil, Guyana, Venezuela, Bolivia, and Colombia. Atlas species run roughly 1–3.5 in. The genus was split out of the much larger, wastebasket genus Moenkhausia in the past couple of decades on the strength of dentition and squamation differences, and its species keep the slim, laterally compressed, silvery body and forked tail typical of open-water Amazonian tetras.
None of the three atlas species is a hobby mainstay under this newer genus name - most that reach aquarists were long sold, and are sometimes still labeled, as Moenkhausia. Makunaima guianensis, the Guiana tetra, is the one most likely to turn up as a wild-collected import from Guyana or the upper Amazon, kept the way most small open-water tetras of this shape are: in loose schools over dark substrate and soft, slightly acidic water. Two of the three atlas species are assessed as Least Concern and the third has not been evaluated, so conservation pressure does not currently look like a concern for the genus.