The one-knife unicornfish or barred unicornfish is common in the coral reefs of the Indian and Pacific Oceans. With the long shape of its body and its slender appearance it looks more like a fusilier than a typical surgeonfish. The barred unicornfish is a planktivore.
Like many other species of the Naso genera it can change its body colour depending on mood or environment, e.g when sleeping on the reef at night it takes on a disruptive mottled pattern as probably shown in above’s image. During the day the one-knife unicornfish is generally yellowish-green in its mid-torso region.
The Naso species in general grow very fast so the one-knife unicornfish should not be housed in tank below at least 10.000 liters.