Marine Animal Encyclopedia
Bignose Unicornfish Naso vlamingii
Unicornfish are so called because many have a hornlike projection on their forehead. However, the bignose unicornfish just has a rounded bulbous snout. At the base of the tail are two pairs of fixed, bony plates that stick out sideways like sharp knives, and the fish can inflict a serious wound on a potential predator. These blades are characteristic of surgeonfish (Acanthuridae), the family to which unicornfish belong.
Usually dark with blue streaks, the bignose unicornfish can pale instantly to a silvery gray. This often happens when the fish is being cleaned by a cleaner wrasse. The bignose unicornfish favors steep reef slopes where it can feed on zooplankton in the open water.