Ocean Surgeonfish

Ocean Surgeonfish


Most frequently found in and around coral reefs and inshore rocky and grassy habitats.

Aquarium Location


Fun Facts
  • Eats large amounts of sand, presumably to aid in the digestion of algae.
  • Ocean surgeonfish have a blade-like spine on each side near the base of their tail that gives the fish its name and can slash a would-be predator by thrashing its tail from side to side.

This species is largely herbivorous, with the majority of its diet coming from green or brown algae scraped from rocks or corals, but will also eat small invertebrates.

Cool Adaptation

Ocean surgeonfish receive their name from the caudal peduncle spine that sits on both sides of the fish’s caudal peduncle (base of its tail). This spine is very sharp and scalpel-shaped, much like the tool used by a surgeon during various procedures. The surgeonfish uses this spine to slice into the flesh of a potential predator when threatened. With a predator at close proximity, a surgeonfish will line up the predator with the base of its tail and thrash from side to side in the water. This thrashing will raise the spine up off of the sides of this fish and slash into the predator in an attempt to deter its advances.

Conservation Connection

The ocean surgeonfish play an important role in their ecosystems as herbivores in coral reef systems. This species feeds largely on the green and brown algae that grow on rocks and reefs, which helps to maintain the overall health of a coral or rocky reef system. Ocean surgeonfish are not important to commercial fishermen. However, they are a popular group collected for display in commercial and private aquaria. Ocean surgeonfish are still considered common despite the collection of this species for use as bait or for display in aquaria. There is currently no special concern/status for the conservation of this species.


Acanthurus bahainus


Ocean surgeonfish range from Massachusetts south along the Atlantic coast to Bermuda, the Gulf of Mexico, the Caribbean, and Brazil


Green or brown algae and small invertebrates

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