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Parrotfish have indirect positive effects on corals by grazing on macroalgae that competes for substrate space with corals. Parrotfish can also have a negative impact on corals by feeding on live coral. Feeding preferences are correlated to jaw morphology in parrotfishes. This study examined the feeding selectivity for two genera of parrotfish (Scarus and Sparisoma) in the Florida Keys to determine the impacts they have on coral reefs. On 14 reefs, fish censuses, behavioral surveys and substrate composition analysis were preformed to calculate selectivity indices for the various substrate types. The indices showed that parrotfish do exhibit selective feeding. Scarus had a significantly higher preference for turf and Sparisoma had a significantly higher preference for macroalgae. These results support life history theory that Scarus are excavators and Sparisoma are grazers as predicted by their jaw morphology. This project was partially supported by the Creative Inquiry program.