Deuterodon is a genus of small to medium tetras in the family Characidae, native mainly to coastal river drainages of eastern Brazil's Atlantic Forest region, with the atlas also recording a species from Guyana. Species in the genus share the general tetra body plan — a laterally compressed, silvery body with an adipose fin — and the genus itself has been reshaped by recent molecular work that separated it from the historically catch-all genus Astyanax, to which many of its species were once assigned. The atlas covers 23 species with adult sizes from about 1–5 in.
Deuterodon has only a modest aquarium-hobby footprint; most species are quiet, unremarkable tetras of more interest to regional ichthyologists and Brazilian fishkeepers than to the wider ornamental trade. Because so many species are confined to single small coastal drainages in one of the most deforested and fragmented biomes in South America, the genus carries real conservation exposure: only about half of the atlas's species have been formally assessed, one is rated Vulnerable, and data are sparse for much of the rest — a pattern typical of restricted-range Atlantic Forest fish that have not yet been thoroughly surveyed.