The Acanthuridae family of fish include surgeonfish tangs and unicornfish, living in tropical seas, generally around coral reefs. Most species are colorful and popular for aquariums. The distinctive characteristic of the Surgeonfish Tangs family is the scalpel-like spines, with one or more blade on either side of the tail, known as “thorn tails.” These are dangerously sharp.
The dorsal fin, anal fin and caudal fins are quite large, extending for most of the length of the body. They have small mouths with a single row of teeth used for grazing on algae. Most species of Ancanthuridae are relatively small with a maximum length of 15-40 cm (6-16″), however, some members of the genus Prionurus and Naso can grow larger with the whitemargin unicornfish (N. annulatus), reaching a length of up to 1 meter (3’3″).
These fish can grow quite quickly in an aquarium, so average growth size and suitability should be checked before adding them to your aquarium.