Brachyplatystoma is a genus of large pimelodid catfish from the major river systems of South America, and it includes some of the biggest freshwater fish on the continent. The atlas's 7 species, recorded from Brazil, Peru, Colombia, Bolivia, Venezuela, Ecuador, French Guiana, and Guyana, span an enormous size range for a single genus — from around 23.5 in up to 3.6 meters — reflecting a mix of moderately sized and truly giant species within the Amazon and Orinoco basins. Like other long-whiskered pimelodids, they are smooth-skinned, scaleless catfish with long barbels and a streamlined body built for a mid-water, migratory lifestyle rather than a bottom-hugging one.
Several Brachyplatystoma species undertake some of the longest migrations of any freshwater fish, with adults traveling great distances between spawning grounds in Andean headwaters and nursery habitat far downstream near the Amazon estuary — a life history that makes them unusually sensitive to dams and other barriers across the basin. Species such as B. rousseauxii (dorado catfish) and B. filamentosum (piraíba) are major commercial and subsistence food fish across their range rather than aquarium species, given their eventual size. That commercial importance is reflected in the atlas's conservation tally, with one species assessed Vulnerable and one Near Threatened alongside three of Least Concern, a pattern consistent with heavily fished, migration-dependent giants under real pressure from both harvest and river fragmentation.