Rio Sorocaba flows through the state of São Paulo, Brazil, as the principal left-bank tributary of the Rio Tietê. The river drains a diverse basin encompassing a wide range of aquatic habitats — from fast-moving headwater streams and long river stretches to marginal lagoons and reservoirs — creating a rich mosaic of environments that support an exceptionally diverse fish community. With 55 species documented across 18 families and 6 orders, the Sorocaba basin ranks among the more biologically complex river systems in interior São Paulo. The vast majority of species present are native to the basin, and sport fishing is widely practiced throughout the watershed, drawing anglers from across the region who target a variety of native and introduced species.