The aim of this study was to determine morphological patterns of the most abundant fish species found in reservoirs with different hydraulic retention times and stages of colonization, considering habitat strata and feeding strategies. Samplings were carried out in six Paraná State (Brazil) reservoirs, and morphological data were obtained from 15 individuals of 17 fish species. Ecomorphological attributes that best segregated species, were selected using Discriminant Analysis. These selected attributes were later used in a Principal Components Analysis (PCA). Differences among reservoirs concerning occupation of the ecomorphological space were tested through analysis of variance (null models). The six reservoirs differed in the occupation of the fish species ecomorphological space and the first two PCA axes explained 66,3% of the total data variability. Thus alterations in water dynamics could a major factor affecting patterns of fish distribution in reservoirs.