Eretmobrycon is a genus of small characins, tetras and their relatives, found in trans-Andean and Central American river systems in Ecuador, Colombia, Panama, Peru, and Costa Rica, an unusual range for tetra-type fish, most of which are concentrated in Amazonian and other lowland South American drainages further east. The atlas covers 9 species, from about 2 in to 4.5 in, generally sharing the silvery, laterally compressed body and adipose fin typical of Characidae, adapted to fast-flowing mountain and foothill streams rather than slow lowland water.
These are mostly fish of regional ichthyological interest rather than established aquarium species, and given the group's limited documentation, care information for most members is genuinely sparse. A few carry evocative common names, Eretmobrycon bayano (Bayano tetra) and E. emperador (emperor tetra, not to be confused with the well-known Colombian Nematobrycon emperor tetra of the hobby) among them, but detailed accounts of their behavior and breeding are largely absent from mainstream aquarium literature. IUCN assessment coverage is thin, with five of nine species Not Evaluated, two Least Concern, one Data Deficient, and one Vulnerable.