Ocean Surgeonfish, Acanthurus bahianus

The ocean surgeonfish is found around coral reefs of the Western Atlantic — off the coasts of Florida, the Bahamas, the Caribbean Sea, the Gulf of Mexico, Bermuda, Brazil, and as far north as Massachusetts. This species will swim in schools, often with other species of surgeonfish.

The oval shaped body of this surgeonfish is bluish-gray to dark brown with yellow markings and a dark marking around the eyes. The fins usually have blue or white markings on them and a pale band around the base of the tail. The ocean surgeonfish can grow to 15 inches in length. The dorsal fin has 9 spines and 23 – 26 soft rays; the anal fin has 3 spines and 21 – 23 soft rays. This fish can live up to ten years.

The spines on the sides of the caudal peduncle can cause a painful sting.

The main diet of this species is algae, but will also feed on weeds, phytoplankton, and other vegetation.

Spawning occur in pairs or in large groups of up to 20,000 fish where the tiny eggs will hatch in about 28 hours after being laid. The larvae settle during the new moon, when it is darker so the larvae are hidden from predators. The eggs are laid on coral patches in shallow water or in sea grass. After hatching the larvae will swim to the reef, where they soon become juveniles. Ocean Surgeonfish may use chemical cues to determine where they settle.

This species is often marketed and eaten, but is primarily used as bait.

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Perciformes

Family: Acanthuridae

Image Caption: Ocean surgeonfish along British Virgin Islands. Credit: D. Gordon/E. Robertson/Wikipedia (CC BY-SA 3.0)