This work provides the first information about feeding habits, trophic ecology and trophic interactions of all examined species(Planiliza parsia, Planiliza planiceps, Mugil cephalus and Chanos chanos) from Cochin Estuary. The result of this work differs from the hypothesis related to omnivorous fishes and concludes that these four omnivorous species live in the same niche zones of the Cochin Estuary with no interspecific conflict. This work will help to give light to the trophic interaction of this species and helps to formulate sustainable resource management.