In the Toledo metropolitan area there are many small headwater streams which suffer the influence of the urbandevelopment (pollution, deforestation, introduction of non-native species). The list of fish species in these sites is importantfor the knowledge on biodiversity in similar environments. Samples were taken bimonthly from October 2007 to February2009 in three sites (headwater, middle and mouth) along of the three streams within urbanization gradient in the city ofToledo. A total of 27 fish species ascribed to 18 Genera, six Orders and 11 Families were collected, among which four speciesare non-native species, and seven are probably new to the science.