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Northwestern Atlantic Ocean Tang
Tangs · Acanthuridae

Northwestern Atlantic Ocean Tang

Acanthurus tractus

A gray-to-brown ocean surgeonfish with pale blue-white fin edges and no dark vertical body bars. Acanthurus tractus is the northwestern Atlantic species formerly grouped with the South Atlantic Acanthurus bahianus.

Care levelExpert

Fish Match's 300-gallon figure is conservative planning guidance, not a documented species-specific minimum from the taxonomic paper.

Recommendation

Would you recommend this fish for a suitable saltwater aquarium?

300+ galRecommended tank
15 inchesAdult size
Semi-aggressive / territorialTemperament
Generally compatibleCoral safety

+ Why you’ll love them

  • A gray-to-brown ocean surgeonfish with pale blue-white fin edges and no dark vertical body bars.
  • 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 300 US gallons or more with suitable swimming space.
  • Fish Match's 300-gallon figure is conservative planning guidance, not a documented species-specific minimum from the taxonomic paper.
  • Requires a consistent feeding routine and stable water.
  • Has sharp tail spines; handle carefully.

Tank and habitat

Recommended volume
300 US gallons or larger; allow for stocking and layout.
Full-grown size
15 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
Fish Match's 300-gallon figure is conservative planning guidance, not a documented species-specific minimum from the taxonomic paper.
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
Supply marine algae and appropriate varied herbivore preparations rather than relying on incidental tank growth. 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
The linked species summary reports about 38 cm standard length, approximately 15 inches excluding the tail. Total swimming and turning space must allow for a larger full-fish length.

Before you buy

Is this fish right for your tank?
Confirm identity and have an adult-sized long aquarium ready; an old ocean-tang label may use outdated taxonomy. The listed volume is editorial planning guidance; the linked biological sources do not establish a tested aquarium minimum.
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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