Psalidodon is a genus of small to medium tetras in the family Characidae, widespread across South and Central America — the atlas's records span Brazil, Argentina, Paraguay, Uruguay, Bolivia, Colombia, Costa Rica, and Belize. The genus was split out of the much larger, long-used genus Astyanax as part of a broader molecular revision of that group in recent years, and it retains the classic Astyanax-type body: a deep-bodied, silvery, laterally compressed tetra with an adipose fin, often marked with a dark humeral spot or caudal blotch. The atlas covers 23 species with adult sizes from about 2–6.5 in.
Locally, Psalidodon species are important as small food and bait fish across their range — several are known regionally as lambari or mojarra and support subsistence fisheries — and a handful circulate in the aquarium trade as hardy, undemanding tetras in the same easy-keeping mold as Astyanax. Because the genus is so recently defined, formal conservation assessment has lagged behind the taxonomy: most of the atlas's species are still unevaluated, with only a small number rated Least Concern or Endangered so far, so the genus's true conservation status is still coming into focus.