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Atlantic Blue Tang

Acanthurus coeruleus

Marine Marine Atlantic and Caribbean

Juveniles begin life vivid yellow before maturing into uniform rich blue beauties with caudal spines. They are relentless open-water swimmers that graze microalgae constantly, requiring vigorous circulation, substantial oxygenation, and plenty of swimming distance. Prone to skin parasites, requiring high water quality and ample dietary vegetable matter.

Also called: Blue tang surgeonfish, Blue barber, Blue doctor, Blue doctorfish.

25 cm adult length, drawn to scale. deep body.

Outgrows a typical home tank. Check this fish against the adult size above before buying a juvenile. The minimum shown is the least it is kept in for good, not a comfortable size.
Saltwater species. The planner judges it with a marine rule set. A reef or fish-only tank takes months to mature and costs more to run than freshwater. See the marine page.

Try it in the planner Opens a tank sized to its minimum with 1 fish added.

What it needs

ItemValueBecause
Adult length 25 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 450 L, at least 180 cm long estimated The least water and floor length this species is kept in for good, as a single fish or smallest group.
Extra water per added fish 100 L estimated What each further fish adds once the minimum is met.
Waste load Class 4 of 5 estimated How much waste an adult makes against its size. Feeds the Load check.
Temperature 24 to 28 C Stock sharing a tank need overlapping ranges.
pH 8.1 to 8.4 Compared with tankmates in the Water check.
Hardness GH 8 to 12, KH 8 to 12 Degrees of general and carbonate hardness.
Flow High Low-flow fish are stressed in a strong current.
Light Bright Matched to the lighting class on the needs sheet.
Group size Single fish is fine Not a schooling species.
Temperament Semi-aggressive Territorial: weak.
Swims in All levels Fish that use different levels share a tank more easily.
Lifespan About 12 years A fish is a long commitment.
Experience Some experience helps A guide to how forgiving the species is of mistakes.
Salinity Marine, about SG 1.023 to 1.025 Needs salt water, a different build and a longer-running tank than a freshwater set-up.

Tags marked estimated are judged from the size and habits of the species rather than measured, so treat them as a sensible default.

Diet and tank layout

Atlantic Blue Tang is an herbivore that swims in all levels of the tank. It is safe with plants. Give it some cover.

Tankmates

Works with

Depends

Avoid

Compare any two fish on the compatibility page, or print the equipment for a stock on the needs sheet. How this is worked out: the method.