Triportheus is a genus of deep-bodied, silvery characins (order Characiformes) native to river systems across northern and central South America, with atlas records from Brazil, Colombia, Peru, Venezuela, Bolivia, Guyana, Paraguay, and Argentina. Atlas species run 3–14 in, sharing a laterally flattened, keel-bellied body and an enlarged pectoral fin base that lets them leap and skitter above the surface to escape predators, a trait behind common names like 'sardine' and 'hatchetfish,' though the genus is not a member of the true hatchetfish family.
Triportheus is mostly a subject of scientific and regional-fisheries interest rather than mainstream aquarium keeping. They are schooling, open-water surface feeders taking insects, fallen fruit, and small fish, and species such as T. albus and T. auritus (both known locally as 'sardine') support small-scale subsistence and artisanal fisheries across the Amazon and Orinoco basins; their size, jumping ability, and comparatively drab coloring keep them out of the ornamental trade. The genus's conservation picture is favorable - 15 of the 16 atlas species are Least Concern - consistent with wide-ranging, abundant populations across major South American rivers.