Bumphead Parrotfish

The bumphead parrotfish, Bolbometopon muricatum, is the largest parrotfish species in the world, with adults reaching well over a meter in length and considerable bulk. It is easily recognized by the large, bony hump on its forehead, which becomes more pronounced with age and is thought to be used in head-butting contests between males as well as to help break coral during feeding. Found across Indo-Pacific coral reefs, it often travels in large schools that graze directly on live coral in addition to algae, making it one of the most powerful bioeroders on the reef, generating substantial amounts of sand through digestion. Due to its large size, slow reproduction, and tendency to sleep in predictable locations, it is highly vulnerable to overfishing and is listed as vulnerable to extinction.

• Massive, thick-set body, the largest of all parrotfish species, often exceeding a meter in length
• Prominent bulbous bony hump on the forehead, most developed in large adults
• Dull green-gray to gray-green overall coloration, often appearing drab compared to smaller, more colorful parrotfish
• Thick lips and a robust, fused beak-like dental plate
• Broad, squared-off tail fin and large body scales
• Frequently seen in schools of a dozen or more individuals, unlike most solitary or pair-forming parrotfish
• Distinguished from all other parrotfish by sheer bulk and the size of the forehead hump

Bumphead parrotfish are found across the Indo-Pacific, from the Red Sea and East Africa to the central Pacific, typically inhabiting outer reef slopes, channels, and lagoons in relatively shallow water down to about 30 meters. They favor areas with substantial live coral cover, which forms a major part of their diet, and are often seen near reef drop-offs and passes with strong currents. Schools of bumphead parrotfish frequently return to the same sleeping sites within reef crevices or caves each night. Because they rely heavily on healthy coral cover, they are considered an indicator of overall reef condition, and their decline often signals broader reef degradation.

Bumphead parrotfish are unusual among parrotfish for regularly feeding directly on living coral in addition to algae, using their powerful fused beaks to break off chunks of coral skeleton, which they grind down and excrete as sand. This bioerosion makes them one of the most influential grazers on Indo-Pacific reefs, shaping reef structure over time. They typically travel and feed in schools, moving along predictable routes across the reef each day and returning to the same resting sites at night. Males use their bony forehead humps in head-butting contests, likely related to establishing dominance. Because they gather predictably in large, visible groups and sleep in fixed locations, they are especially susceptible to spearfishing and overharvesting.