Rio Melchior is a stream flowing through the Federal District of Brazil, situated at approximately 15°55'S, 48°13'W in the central plateau region of the country. As part of the broader watershed system of the Federal District, the river shares its drainage basin with several other notable waterways, including the Ribeirão Melchior, which flows nearby and supports a similarly diverse community of native and introduced fish species. The stream environment is characteristic of the Brazilian Cerrado biome, where gallery forests line the banks and the waterway supports a rich assemblage of tropical freshwater fish. Rio Melchior attracts local anglers seeking a variety of species in an accessible stream setting within the Federal District.