This video, filmed on location in the Maldives, shows a school of Surgeonfish swarming around a coral formation. Surgeonfish are members of the Acanthuridae (“thorn tail”) family, which also includes tangs and unicornfishes. The family includes about 80 species in six genera, all of which are marine fish living in tropical seas, usually around coral reefs. Many of the species are brightly colored and popular for aquaria.

The distinctive characteristic of the family is the spines, one or more on either side of the tail, which are dangerously sharp. Both the dorsal and anal fins are large, extending for most of the length of the body. The small mouths have a single row of teeth used for grazing on algae.^[1]

Most species are relatively small and have a maximum length of 15-40 cm (6-16 in), but some members of the genus Acanthurus, some members of the genus Prionurus, and most members of the genus Naso can grow larger, with the whitemargin unicornfish (N. annulatus), the largest species in the family, reaching a length of up to a meter (3,3 ft). These fishes can grow quickly in aquariums so it is advisable to check the average growth size and suitability before adding to a marine aquarium.