Fish species composition is presented for three streams from the upper Tocantins River. Bimonthly samples were taken by electrofishing. Fish communities in the Água Boa, Acaba Saco and Cavalo streams were composed of 35, 28 and 36 species, respectively. Characiformes and Siluriformes were the most abundant among the four registered orders. Con-stancy analyses revealed that all streams had a high number of occasional and rare species. The high diversity was registered at Acaba Saco stream, followed by Cavalo and Água Boa streams.
Amazonian Basin; Tocantins River; Serra da Mesa; Streams; Fish Community