Blue Unicornfish

Naso caeruleacauda

The Blue Unicornfish, also known as the bluetail unicornfish, is a marine fish belonging to the family Acanthuridae. This species is recognized by its distinctive blue caudal fin, which is its most notable feature. The body coloration ranges from bluish-grey to brownish-grey, with a paler, sometimes yellowish hue on the lower body, and a yellow patch beneath the pectoral fins. The dorsal profile of the head is straight, with a noticeable bulge between the eyes and nostrils. It can grow up to 40 cm in length and weigh up to 1.1 kg. This species is found in the western central Pacific, particularly around the Philippines, Indonesia, and the Great Barrier Reef in Australia. It has also been recorded off northeastern Madagascar. The Blue Unicornfish typically inhabits reef slopes and is often found in schools over steep, seaward-facing reef walls at depths ranging from 15 to 45 meters. The Blue Unicornfish is a schooling species, primarily feeding on plankton. Divers encountering this fish can expect to see it actively swimming in groups along outer reef walls. The IUCN lists this species as Least Concern.