SURGEONFISHES 
ACANTHURIDAE
General:
Most surgeon fishes graze on benthic algae and have a long intestine; some feed mainly on zooplankton or detritus.

Surgeon fishes are able to slash other fishes with their sharp caudal spines by a rapid side sweep of the tail.

Pelagic spawners.

Very small ctenoid scales. A small terminal mouth with a single row of close-set teeth. All have a deep compressed body with the eye high on the head and a long preorbital bone. Single unnotched dorsal fin with 4-9 spines and 19-31 rays; anal fin with 2 (only Naso) or 3 spines and 19-36 rays; pelvic fins with 1 spine and 3 (Naso and Paracanthurus) or 5 rays
Blue Tang
Acanthurus  coeruleus
Doctorfish
Acanthurus chirurgus
Ocean Surgeonfish
Acanthurus bahianus
Etymology
Greek, akantha = thorn + oura = tail