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Atlantic Blue Tang
Tangs · Acanthuridae

Atlantic Blue Tang

Acanthurus coeruleus

A deep-bodied Atlantic surgeonfish that changes from a yellow juvenile to a blue adult with a pale or yellow tail spine. This is a different species from the Blue Hippo Tang and needs substantial adult swimming space.

Care levelIntermediate

Adult size reports exceed the smaller aquarium-trade figures: natural-history references record about 39 cm, or 15.5 inches. Allow for that larger adult.

Recommendation

Would you recommend this fish for a suitable saltwater aquarium?

180+ galRecommended tank
15.5 inchesAdult size
Semi-aggressive / territorialTemperament
Generally compatibleCoral safety

+ Why you’ll love them

  • A deep-bodied Atlantic surgeonfish that changes from a yellow juvenile to a blue adult with a pale or yellow tail spine.
  • Grazes marine algae as part of a balanced feeding plan.
  • Generally compatible with corals when appropriately housed.

! Things to consider

  • Needs adult-sized housing: plan for 180 US gallons or more with suitable swimming space.
  • Adult size reports exceed the smaller aquarium-trade figures: natural-history references record about 39 cm, or 15.5 inches. Allow for that larger adult.
  • Requires a consistent feeding routine and stable water.
  • Has sharp tail spines; handle carefully.

Tank and habitat

Recommended volume
180 US gallons or larger; allow for stocking and layout.
Full-grown size
15.5 inches (maximum adult size)
Tank footprint and swimming space
Choose a long rectangular aquarium with open swimming lanes and room to turn. Leave space around rockwork; a tall narrow tank is a poor substitute for swimming length.
Tank maturity
6 months recommended
Use an established, fully cycled aquarium with stable filtration and productive grazing surfaces. Confirm water stability and reliable feeding access before introduction. Suggested tank age is a planning guide, not proof of readiness. Complete cycling, stable water and the right food supply are essential.
Habitat and equipment
Provide good circulation and gas exchange. Arrange secure rockwork for shelter and grazing, keep open water available, and use a secure lid. Take care around the sharp tail spines.

Care and compatibility

Temperament
Semi-aggressive / territorial
Why this care level
Adult size reports exceed the smaller aquarium-trade figures: natural-history references record about 39 cm, or 15.5 inches. Allow for that larger adult.
Suitable tank mates and conflicts
Many appropriately sized marine community fish may be suitable. Other tangs, especially similar-shaped species, require particular care and substantially more space.
Alone, pair or group
A single tang is the simpler plan. Keeping several requires additional space, individual assessment and a way to separate incompatible fish; wild groups do not establish an aquarium stocking rule.

Corals and invertebrates

Coral safety
Generally compatible
Generally compatible with corals, but observe the individual. Algae grazing should not be mistaken for a guarantee that no picking will occur.
Shrimp safety
Generally compatible
Generally compatible with ornamental shrimp; monitor introductions and individual behavior.
Snail safety
Generally compatible
Generally compatible with snails. Continue observing grazing behavior around small invertebrates.
Clam safety
Generally compatible
Usually compatible, but individual picking is possible. Monitor clam mantles and other sessile invertebrates, especially if feeding is inadequate.

Food and feeding

Diet
Herbivore; marine algae and varied prepared foods
Feeding plan
Provide marine algae and a varied herbivore feeding routine; it should have access to grazing surfaces without being chased away. Offer food consistently and check body condition; natural grazing is a supplement, not a complete feeding plan.
Prepared or live food
Marine algae sheets, suitable herbivore pellets and varied marine frozen preparations can be offered. Confirm the individual accepts the foods you can provide.

Water conditions

Temperature
72–78 °F (22–26 °C) is a commonly published aquarium reference range. Maintain stable conditions and consider the needs of the whole community.
Specific gravity
Specific gravity 1.020–1.025 appears in common species-care guidance. Match the needs of corals and other inhabitants, and avoid abrupt changes.
pH
pH 8.1–8.4 is the published marine aquarium reference range used here; maintain stability rather than chasing a single reading.

Long-term care

Lifespan
The linked references do not establish a reliable typical captive lifespan for this profile. Plan for long-term care and maintain a realistic adult housing commitment.
Growth and future planning
Adults may reach about 15.5 inches. Growth depends on the individual and conditions; juvenile purchase size should not determine the long-term aquarium.

Before you buy

Is this fish right for your tank?
Confirm Acanthurus coeruleus. A yellow juvenile and a blue adult can be the same species; the minimum volume is only a starting point for adult housing.
Buying checklist
Ask to see the fish eat. Look for a well-filled body, clear eyes, intact fins and normal swimming and breathing. Plan quarantine and confirm the seller’s species identification and feeding routine.

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