Rio Turvo is a river winding through the interior of São Paulo state, Brazil, flowing through a landscape shaped by agricultural land, riparian corridors, and floodplain features characteristic of the upper Rio Paraná basin. The river is notable for its network of marginal lagoons — seasonally connected oxbow lakes and floodplain pools that serve as critical habitat for a remarkably diverse fish community. Research conducted near the municipalities of Icém and Nova Granada has documented 52 fish species in the river's marginal lagoons alone, representing 17% of the 310 species recorded for the entire upper Rio Paraná system — a figure that surpasses species counts from comparable marginal lagoon studies on the Sorocaba, Paranapanema, and Mogi-Guaçu rivers. This biodiversity makes Rio Turvo a genuinely exceptional destination for anglers interested in tropical freshwater fishing.