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Parrotfish, The parrotfishes (family Scaridae) are among the most important herbivores on the reef. They get their name from their bright colors, curious flapping "flight" (much like wrasses), and their strong, birdlike beaks, which they use to scrape algae and other living matter from rocky surfaces. In so doing they inevitably take in great quantities of coral rock. This is ground down by powerful sets of teeth in the throat so that the organic material can be more easily digested, The waste product of the feeding activities of parrotfish is coral sand—a major component of Indonesian beaches especially on the offshore islands.

Parrotfishes are protogynous hermaphrodites that undergo a series of color changes with age and sexual status. Primary phase parrotfish—whether males or females—are exceedingly difficult to identify, all being relatively drab grey or rust-colored. The terminal males are striking, however, usually green with bright markings, particularly around the cheeks and eyes, In most species the primary phase is made up of mixed males and females (diandric); in others the primary phase is all females (monandric).