Blackspine Unicornfish

Naso minor

The Blackspine Unicornfish, also known as the slender unicornfish, is a species of marine fish found in the Indo-Pacific region. This fish is relatively slender, with a body length about three times its depth. It features a smoothly rounded head without any protuberance, and its overall coloration is grey with a purplish-grey head, fading to white on the underside. Notable features include blackish lips, a yellow caudal fin, and a single bony plate on each side of the caudal peduncle with a large keel and forward-pointing spine. During courtship, males exhibit a color change with a black upper body and a white stripe along the flanks. The Blackspine Unicornfish inhabits coastal reefs to outer reef slopes, often swimming along the upper edges of drop-offs in small groups. It has a wide but somewhat localized distribution, recorded from Mozambique to the Philippines, and as far north as Taiwan and south to Australia. This species is typically found at depths ranging from 8 to 55 meters. Feeding primarily on zooplankton, the Blackspine Unicornfish forms aggregations to feed well above the reef bottom. It also descends to the reef front to be cleaned by the bluestreak cleaner wrasse. The IUCN lists this species as Least Concern.