Atlantic blue tang (Acanthurus coeruleus) care guide

Group
Marine fish
Other names
Blue tang, Blue doctorfish, Blue doctor, Blue barber, Yellow doctorfish, Yellow barber, Blue tang surgeonfish
Family
Acanthuridae (surgeonfishes and tangs)
Origin
Western Atlantic from New York to Brazil, including Florida, the Caribbean and Ascension Island; introduced to the Mediterranean. Coral reefs, seagrass and rocky inshore areas
Water
saltwater
Maximum size
41 cm
Temperature
24–27°C
pH
8.1–8.4
Hardness
Salinity SG 1.023–1.026
Minimum tank
700 litres
Care level
intermediate
Temperament
semi_aggressive
Reef safe
yes

Care

Tank and decor: an active, open-water swimmer that needs a long tank with plenty of swimming room, live rock for grazing and strong, well-oxygenated flow. Minimum tank: about 700 litres (an estimate based on its 41 cm adult size and active swimming). Water: our sources give no species-specific figures, so the values here are general marine aquarium guidance, not species-specific: 24–27 °C, pH 8.1–8.4 and specific gravity 1.023–1.026. Keep nitrate low and the water well oxygenated. Behaviour and identification: adults are blue; juveniles are yellow, passing through a blue-and-yellow stage. The list says it is less aggressive than the Achilles or powder blue tangs. Wikipedia notes that juveniles are solitary and territorial, while adults may be territorial, school or wander, and that it sometimes acts as a cleaner, grazing algae and parasites off turtles. The list gives a maximum size of 16 in (about 41 cm); Wikipedia gives 39 cm. It is common in the trade. The IUCN status is not stated in the article, which says the species is not under human threat. Safety: like all surgeonfishes it has a sharp, scalpel-like spine on each side of the tail base that can cut hands and get caught in nets. Use a container to move it. Selling: our policies require the adult size and long-term tank needs to be stated clearly in the listing. Large fish must travel by a specialist live-animal courier (see the Livestock shipping guide). Sources: Wikipedia, List of marine aquarium fish species (en.wikipedia.org/wiki/Listofmarineaquariumfishspecies); Wikipedia (en.wikipedia.org/wiki/Acanthuruscoeruleus). Checked October 2026.

Diet

Herbivore. Wikipedia says it eats filamentous algae, detritus and plankton, and that juveniles feed almost non-stop. Offer marine algae every day (dried nori on a clip, spirulina- and seaweed-based flakes and pellets, frozen herbivore foods) and feed several times a day.

Breeding

Our sources for this page do not describe breeding. Tangs spawn in open water and have long-lived planktonic larvae, and almost all aquarium tangs are wild-caught.

Compatibility and tank mates

Reef safe: it leaves corals and invertebrates alone, though it grazes algae. It can be territorial towards other tangs, especially similar-looking ones, so add tangs at the same time in a large tank, or keep one per tank.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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