Fish, Machado River basin, Cacoal urban area, state of Rondônia, Brazil

The Pirarara and Tamarupa rivers are two urban tributaries of the Machado River in Cacoal municipality, state of Rondônia (RO), Brazil. Here we report a list of species of fishes from urban areas of Cacoal, being the first ichthyological study in this region. Field work at Cacoal was carried out from November 2004 until July 2005, using gill nets, casting nets, and long lines. Two hundred and twenty-two specimens were collected, and are distributed in 48 species, 14 families and 4 orders. The most representative order was Characiformes, with seven families and 23 species, followed by Siluriformes, with three families and 20 species