#782: Unicornfish

Unicornfish are a number of Naso species, related to tangs and surgeonfish. He is named for the horn-like appendage between his eyes, which tends to be longer in males. He grazes on algae, shifting to zooplankton if his horn gets too long for him to successfully scrape algae from the substrate. Generally fairly drab in colour, some species will change their colouration in response to stimuli - such as when he is courting a female, or seeking the assistance of cleaner wrasse.

This is a Bluespine Unicornfish.