Steephead Parrotfish

Overview

The Steephead Parrotfish (Chlorurus microrhinos) is a large, widely distributed reef fish found throughout the tropical Pacific Ocean. It is easily recognized by its robust body and, in large adults, a distinctive, blunt-headed profile caused by a prominent hump on the forehead.

Distribution & habitat

This species is common across the Indo-Pacific, ranging from Indonesia and the Philippines to the Great Barrier Reef, New Caledonia, and eastward across Oceania. It inhabits a variety of reef environments, including lagoons, inshore reefs, and exposed seaward reef slopes.

Appearance

Adults typically display a greenish-blue coloration, often highlighted by a brilliant blue band that extends behind the corner of the mouth and a wide blue patch along the head. While most individuals are blue-green, rare yellowish-tan color phases occur. Juveniles look significantly different, starting as black with horizontal white stripes before gradually transitioning to their adult colors as they grow. As they mature, their tail fin changes from rounded to a crescent shape with elongated lobes.

Biology & behavior

Steephead Parrotfish are active grazers that play a vital role in reef health. Juveniles are generally solitary, while larger adults often congregate in schools to forage. They are known to be fast-growing, with a lifespan reaching approximately 15 years. Like other parrotfish, they are oviparous and engage in distinct pairing during breeding cycles.

Feeding

These fish are important excavators on the reef. They feed primarily on benthic algae and detritus by using their strong, beak-like dental plates to scrape and crunch into dead coral substrates, which helps manage algal growth and contributes to the creation of carbonate sand.