The two Cichlid fishes Etroplus suratensis and Tilapia mossambica thrive well in almost identical environments along the west coast of India. During the immature stage (65-105 mm) both feed on phytoplankton, algae, roots of aquatic weeds, etc. But during the second stage of maturity (106-146 mm) both become omnivorous, T. mossambica showing a preference for protozoans, coperpods while E. suratensis prefers zooplankton During the ripe condition (147-187 mm) T. mossambica consumes more of larvae and eggs of fishes while E. suratensis turns more to detritus feedirg.

Chemical analysis of the stomach contents (protein, fat and carbohydrate) shows that T mossambica consumes the most nutritious substances during its first and second stages of growth. In E. suratensis it could be observed that the protein, fat and carbohydrate are decreasing from the size range of 65-105 mm to 147-187 mm and the ash content is increasing vice versa. Significant differences exist in the stomach contents of these two species.