The Rio Araguaia is one of Brazil's great rivers, flowing northeast from the Goiás-Mato Grosso border region before joining the Tocantins River near the town of São João. This remarkable waterway occupies a unique ecological position as a transition zone between the Amazon rainforest and the Cerrado savanna, giving it extraordinary biodiversity both above and below the waterline. The river supports an exceptionally rich fish fauna, with scientific surveys documenting over 89 species across 21 families in the upper-middle portions alone, representing five major orders of fish. The Araguaia's floodplain system creates a mosaic of lentic (still water) and lotic (flowing water) environments, each harboring distinct fish communities and offering varied angling opportunities. Tourism along the river is heavily centered on ecotourism and sport fishing, drawing anglers from across Brazil and internationally who come to experience the region's remarkable aquatic diversity.