Two piscivorous fishes, peacock bass (Cichla monoculus Spix & Agassiz, 1831) (Perciformes) and piranha (Pygocentrus nattereri Kner, 1860) (Characiformes), were introduced in some Rio Doce valley lakes (19º50'S, 42º40'W) for sport fisheries enhancement. As a consequence, small individuals and species were practically vanished in the host lakes. In this study, the effects of peacock bass and piranha introductions on the diet of a native piscivorous fish, the trahira - Hoplias malabaricus (Bloch, 1794) are presented. Trahira's diet from three lakes were was compared with the stomach contentsdiet of trahira's living in another between three lakes with and three withoutstocked with the piscivorous species peacock bass and piranha. In the lakes with introduced fishes species, the consumption of fish was significantly smaller and this food item have been this item partly replaced by aquatic invertebrates. This shift on of trahira's diet to the low abundance of its original prey, is attributed to the small fishes. This diet plasticity adaptative capacity he diet plasticity detected for trahira might be allowing its maintenance in the lakes with peacock bass and piranha.
Cichla; Pygocentrus; Hoplias malabaricus; diet; species introduction