A bag-seine net (18-22 mm bar length mesh size) was used to collect two native, the Albanian barbel, Barbus albanicus Steindachener, 1870 and the chub, Leuciscus cf. svallize (Heckel et Knerr, 1858) and one introduced, the pumpkinseed, Lepomis gibbosus (Linnaeus, 1758), fish species of the Tavropos reservoir (western Greece). The soamtic lengths were linearly correlated to each other for all three species. B. albanicus and L. cf. svallize exhibited negative allometric growth, while the L. gibbosus grew isometrically. The mouth dimension were linearly or exponentially correlated to body size for all species. However, the mouth morphology differed among the species indicating differences in foraging ability and resource utilization. The lifespan of B. albanicus, L. cf. svallize and L. gibbosus in Tavropos reservoir was 21, 9 and 3 years respectively. The corresponding growth parameters were: L∞ = 47.0 cm, K = 0.064 yr-1, t0 = -2.76 yr for B. albanicus, L∞ = 24.3 cm, K = 0.257 yr-1, t0 = -1.46 yr for L. cf. svallize and L∞ = 11.9 cm, K ´0.506 yr-1, t0 = 1.67 yr for L. gibbosus.