Abstract: The objective of this study was to analyze the seasonal behavior of the icthyofauna, considering the trophic relationships between the species that live in Camaronera Lagoon, their food composition, diversity and trophic amplitude, as of the captures obtained in Camaronera Lagoon inlet during February-June, 2000. We realized seasonal tables of the fish species and items of identified foods. The data were grouped in diurnal and nocturnal samplings in order to know the abundance, specific richness, evenness and McNaughton’s community dominance index. The amplitude of the niche was calculated as of Levin’s standardized index. Costello’s graphic method was used to evaluate the preference and feeding behavior of any given type. The families with more species were Cichlidae, Eleotridae and Gobiidae. The most representative species regarding biomass and abundance were Gambusia affinis, Petenia splendida, Cathorops melanopus, Diapterus auratus and Bathygobius soporator.