Sparisoma viride - the Stoplight Parrotfish

The stoplight parrotfish is one of the most colorful fish of Caribbean reefs. Its name comes from the bright green body with yellow marks on the tail and red marks on the head and red dorsal and anal fins shown by individuals in the terminal phase.

Like other parrotfishes it feeds on coral, breaking pieces off with a parrot-like beak and grinding it with teeth in the throat. The ground-up coral skeletons are deposited in piles after traveling through the digestive tract, becoming a significant fraction of Caribbean sand.

The parrotfish has an unusual life history. The larva starts life with no eyes, no mouth, and no coloration. Each fish can be either a male or a fish which is female in the initial reproductive stage, but can become male in the terminal phase. The initial phase coloration is shared by males and females, and consists of a mottled brown/gray body becoming red towards the belly, with red fins. Fish which are born male will keep this initial coloration throughout life, but the fish which change from female to male transform to the terminal color scheme describe above.

I recently had the pleasure of seeing the stoplight parrotfish while snorkeling off Looe Key, Monroe County, Florida: