Acanthuridae is a family of forked-tailed fish, sometimes called by a variety of different names, including tang, surgeonfish, unicornfish and more. There are over eighty different species in the Acanthuridae family all who have very sharp and dangerous spines on their tail, which fork out at their rear. Usually the spines lie flat against the sides of the fish but if they are angry or scared the spines stick out and can be used to lash out at any perceived threat as the fish thrashes its tail about. They have small mouths with only one row of teeth which is sufficient for their vegetarian diet of algae. Most species of this curious ocean-dweller are medium sized, but they vary in length between 6 and 16 inches (15-40 cm). One particular species however, the whitemargin unicornfish, can grow up to 3.3 feet (1 m)!

whitemargin unicorn

Most of the various species of tang that populate the world’s oceans are brightly colored and striking to look at. They inhabit the tropical seas and most often will be found nearby coral reefs. The achilles tang is a deep inky black with bright white and orange accents on the fins and tail. The powder blue surgeonfish is a vibrant shade of azure with an electric yellow spine. Perhaps the most spectacular salt-water fish in the family is the regal tang, which is a princely shade of purple with black accents and a neon-yellow/green tail.

Though some individual species feed alone, most surgeonfish travel and feed together in groups. Groups of tang will find and band together to protect stores of algae, which the group will follow as it floats through the ocean, like a mobile buffet. In the United States and abroad, these brightly colored fish have become a favorite in home aquariums, and are a popular addition to any fish-lover’s tank.