Rainbow parrotfish

Photo: Karl Questel · © all rights reserved

The rainbow parrotfish is the largest herbivore on Caribbean reefs and a keystone species for reef structure: its beak-like fused teeth scrape algae from dead coral rock, and its digestive process produces the fine white sand that forms Caribbean beaches. Terminal-phase males can exceed a metre in length and display vivid turquoise, green, and orange coloration. Their populations have declined sharply outside reserves due to spearfishing, making the Cousteau Reserve a critical refuge.