The Iriri River is one of the main tributaries of the Xingu River and is characterized by being relatively shallow and rocky, with transparent warm waters (33 degrees Celsius) during the low water season. Like the Xingu, it has a very rich ichthyofauna, some of them especially adapted to rapids (reophilic fish). In this video you can see quickly how the waters of Iriri look like, as well as some of its inhabitants: pacus (Myloplus rubripinnis, Myleus setiger), piaus (Hypomasticus julii, Leporinus fasciatus, Leporinus maculatus, Leporinus tigrinus), cichlids (Geophagus argyrostictus, Teleocichla preta), tetras (Moenkhausia heikoi and others) and, of course, the “trairão” or Monster Wolf Fish (Hoplias aimara).