Grazing of the lambari fish Deuterodon iguape is associated with mouth morphology

For a better understanding of fish feeding biology it is desirable to know not only the food items ingested by the species but also the anatomical structures and feeding tactics that enable individuals to access specific food. Deuterodon iguape is an omnivorous and small-sized Characidae from coastal Atlantic rainforest. We describe the grazing tactic of D. iguape and discuss the associated mouth structures that enable individuals to access algae and debris from bedrocks in Atlantic forest streams. Mouth structures acting together with body inclination of individuals probably confer advantages to the species scraping foraging strategy (herein called hard substrate scraper while laterally inclined) and optimize the food intake. The ability of D. iguape to access specific food resources in Atlantic forest streams may confer ecological advantages in relation to other fish species that do not have as much trophic plasticity.