Roeboides is a genus of characins found from Central America down through much of tropical South America, with the atlas's records spanning Brazil, Panama, Colombia, Venezuela, Peru, Costa Rica, Ecuador, and Guyana. What sets the genus apart from most other 'tetras' is diet: many Roeboides species are lepidophagous, specialized scale-eaters that approach other fish and rasp scales from their flanks with an unusual jaw structure, rather than feeding on the more typical characin menu of insects, seeds, and algae. Outwardly they show the classic characin build -- a laterally compressed, silvery, often deep-bodied fish with large eyes suited to a furtive, often crepuscular or nocturnal feeding strategy. The atlas covers 21 species with adult sizes from about 2–8.5 in.
Because of this specialized, somewhat opportunistic feeding style, Roeboides is a genus of mostly scientific interest rather than a fixture of the aquarium trade -- its scale-eating habit makes most species poor tankmates for a mixed community aquarium. Species names such as Roeboides descalvadensis, the Parana scale-eating characin, and the widely distributed R. affinis and R. microlepis (Glass Characin, Smallscale characin) illustrate the pattern well. Conservation status for the genus looks comfortable overall, with the large majority of assessed species rated Least Concern and only a couple listed as Data Deficient, consistent with a wide-ranging, adaptable group of predators rather than a narrowly distributed one.