🏝️ On tropical beaches, a large part of the sand comes from the parrotfish, a marine animal named for its bright colors and its beak-like fused teeth. This beak allows it to scrape algae off coral. While feeding, it also ingests coral fragments, helping reefs grow by keeping algae in check. By crushing these calcareous debris, the parrotfish contributes to sand formation. Once passed through its digestive system, undigested coral fragments become fine sand grains that settle on the seafloor and