Rio Sarapuí is a tributary river flowing through the state of São Paulo, Brazil, as part of the greater Sorocaba River basin — itself the main left-margin tributary of the Tietê River. The river drains through a landscape that is a mosaic of natural forest patches, cerrado savannah, reforested areas, pasture, and agricultural land including corn and sugarcane cultivation. This varied land use shapes the river's character and the diversity of fish communities found along its course. The Sorocaba basin, which includes the Sarapuí as one of its principal tributaries, covers a drainage area of approximately 5,269 km², encompassing 18 municipal districts. The Rio Sarapuí is a lotic (flowing water) environment that supports a notably diverse freshwater fish fauna, making it an appealing destination for anglers interested in tropical freshwater species.