To evaluate the environmental quality and patterns of diversity of fish species from an altered urban stream, we analyzed habitat quality, water velocity and fish species distribution. In order to include a larger amount of environments and considering the distinct physical characteristics and human influence, five stream sites were seasonally sampled. A total of 5,426 individuals, being 12 species and 6 orders, were collected. The degree of environmental alteration at each sampling site was determined through the analysis of habitat diversity and water velocity. The intermediate sites showed higher species richness as the upper sites were the most altered ones. The lower sites showed adverse physical characteristics to the permanence of some species. These results indicated that hydrological and geomorphological characteristics should influence the aquatic biota richness. Nonetheless, it was found that native species still find favorable places to their development, even with exotic species that have became abundant and are potential competitors in environmental and resources exploration.
fish diversity; habitat diversity; streams; urban area; water quality