The fish species appearing occasionally in the catches belonged to two feeding groups: 1) species feeding mainly on clacocerans but with detritus as an important complementary food category (common carp and white bream), and 2) species feeding mainly (trout) or exclusively (largemouth bass) on aquatic and terrestrial macroinvertebrates (Fig. 4). Among these species the trout was the only native one. It was captured only during spring and summer. Largemouth bass showed a narrower dietary breadth than trout. This exotic species was captured only during spring. Individuals captured fed exclusively on aquatic and terrestrial macroinvertebrates. During spring, the common carp fed mainly on cladocerans, whereas in summer the decrease of cladoceran consumption was compensated by an increase of detritus consumption. White bream were captured only during summer in the reservoir. This exotic species feeds both on cladocerans and detritus as main food categories. The analysis of the feeding strategy by means of the Amundsen et al. method indicated that white bream was the species with most generalist feeding habits (Fig. 5), whereas trout and largemouth bass were specialist feeders with a narrow diet breadth (Table 2)