Acanthurus coeruleus is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs, found in the Atlantic Ocean.

[1] Acanthurus coeruleus is present in the western Atlantic Ocean from New York to Florida, Mexico and Brazil, and Ascension Island in the Mid-Atlantic.

As juveniles, the edges on their dorsal and anal fins and the rings around their eyes are purple-blue, blue or blue-green.

[5] Atlantic blue tangs inhabit coral reefs and inshore grassy and rocky areas, where there is a high prevalence of algae.

[citation needed] The blue tang's stomach and intestinal lining are proficient at absorbing crushed cellular content, but are not very effective at processing cellulose.

This digestive system inefficiency leads blue tangs to spend more time and resources on foraging on a very abundant and fast-growing food source in close proximity.

[10] This model states that competitors should adjust their distribution in accordance with habitat quality such that each individual will gain the same amount of resources.

[2] When acting as clients, blue tangs normally approach cleaning stations inhabited by cleaner gobies.

Cleaners must be careful because the spine on both sides of the caudal peduncle are sharp and can inflict painful wounds.

Injured blue tangs are found to spend more time in cleaning stations compared to those further along in the healing process.

Additionally, schooling allows fish to better overcome food defense by others, and wandering allows for individual movement to feeding areas, cleaning stations, and other resources.

[14] Fish in schooling mode swim fast, eat at intermediate rates, and are not aggressive, even though they are often chased by damselfish.

[15] Wandering is found most often in the reef back zone (enclosed region with irregular patches of algae, rock and sand) and during the morning.

[16] While not under human threat, the Atlantic blue tang is caught for commercial fishing, but maintains little importance to Caribbean industry.

These fins can cut very deep into human skin and have been known to result in infections, mainly characterized by swelling and discoloration.