Bluespine Unicornfish

Naso unicornis

The bluespine unicornfish (Naso unicornis) is a large surgeonfish reaching up to 70 cm. Adults develop a prominent horn-like projection on the forehead and have two fixed, bright blue keel-shaped spines on each side of the caudal peduncle. The body is olive-grey to brownish. Found across the Indo-Pacific from the Red Sea and East Africa to Hawaii and French Polynesia, it inhabits reef flats, lagoons, and outer reef slopes at depths of 1 to 80 meters. This herbivorous species feeds primarily on coarse leafy brown algae. It is often seen in large schools on reef flats and in channels. The distinctive horn and vivid blue tail spines, combined with its large size and schooling behavior, make it one of the most recognizable and photogenic surgeonfish species on tropical reefs.