Gephyrocharax is a genus of small tetras in the family Characidae, native to Pacific- and Caribbean-slope rivers of northwestern South America and southern Central America — the atlas's records span Colombia, Panama, Bolivia, Venezuela, Ecuador, Peru, and Trinidad and Tobago. Species are slim, silvery, schooling fish, mostly under 2.5 in, typical of small forest streams and tributaries rather than large rivers. The genus sits within the characid subfamily Stevardiinae, a South and Central American lineage in which many genera show pronounced sexual dimorphism, with males carrying modified fins used in close-range courtship display. The atlas covers 13 species.
Gephyrocharax rarely appears in the aquarium trade under its own name; most stevardiine tetras sold to hobbyists come from better-known relatives, and the handful of Gephyrocharax species with common names in the atlas, like the bareback tetra (G. atracaudatus), steel tetra (G. melanocheir), and Venezuelan tetra (G. venezuelae), are seen mostly among characin specialists rather than the general trade. Conservation data for the genus are mixed: the IUCN tally leans least concern but carries a meaningful data-deficient share, reflecting how many of these small stream fish have had only limited survey attention.