Background. Some studies in the Neotropical ecozone evaluated the correlation between the ichthyofauna and the physical and chemical characteristics of streams. This study aimed to estimate the environmental quality of Neotropical streams through quality protocols and diversity indexes. The hypothesis is that it is possible to identify fish species indicators of variables and streams quality associated to environmental conservation and degradation. Materials and methods. Sampling occurred quarterly from October 2012 to July 2013, totalling four phases of field surveys in three sample units on each stream (Água dos Anjos Stream, Monjolinho Stream, and Ubá Stream, upper Paraná River basin) in southern Brazil. The Indicator Value Method (IndVal) was used to relate the ichthyofauna (abundance and relative frequency of fish species) to physical and chemical variables and streams and their respective environmental characteristics. Results. A total of 33 species were analysed as possible indicators by the IndVal method, and 21 species showed a significant relation (P < 0.05) to one or more environmental variables. The exotic Poecilia reticulata Peters, 1859 was best linked to low-oxygen water. Bryconamericus iheringii (Boulenger, 1887) was an indicator of the stream with the worst environmental quality among the analysed streams, and also indicated significantly lower extent of riparian vegetation (<6 m) and unstable substrate. Geophagus brasiliensis (Quoy et Gaimard, 1824) was also indicator of the stream with inferior environmental quality and low of riparian vegetation (<6 m). On the other hand, Trichomycterus diabolus Bockmann, Casatti et de Pinna, 2004 was indicator of diverse habitats environments, as it was linked to higher extent of riparian vegetation (>18 m) and high water oxygenation. Conclusion. The fish species: P. reticulata, B. iheringii, and G. brasiliensis were indicators of inferior environmental quality, and T. diabolus was an indicator of superior quality, and its abundance can characterize as important bio-indicators of environmental characteristics of Neotropical streams.

fish conservation, Indicator Value Method, Neotropical fishes, environmental quality of streams