Tangs · Acanthuridae
Care levelIntermediate
Convict Tang
Acanthurus triostegus
Six dark vertical bars cross a pale silver body, giving the Convict Tang its recognizable pattern. An active grazer, it needs an established aquarium and tank mates that will let it feed and settle.
Can be outcompeted or bullied by more assertive tangs; watch feeding access rather than relying on a broad temperament label.
Recommendation
Would you recommend this fish for a suitable saltwater aquarium?
130+ galRecommended tank
8 inchesAdult size
Semi-aggressive / territorialTemperament
Generally compatibleCoral safety
+ Why you’ll love them
- Six dark vertical bars cross a pale silver body, giving the Convict Tang its recognizable pattern.
- 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 130 US gallons or more with suitable swimming space.
- Can be outcompeted or bullied by more assertive tangs; watch feeding access rather than relying on a broad temperament label.
- Requires a consistent feeding routine and stable water.
- Has sharp tail spines; handle carefully.
Tank and habitat
- Recommended volume
- 130 US gallons or larger; allow for stocking and layout.
- Full-grown size
- 8 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 aquarium with stable filtration and productive grazing surfaces. Six months is a planning guide, not proof of readiness: cycling, water stability and feeding access matter more than calendar age. 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
- Can be outcompeted or bullied by more assertive tangs; watch feeding access rather than relying on a broad temperament label.
- 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 regular marine algae and suitable herbivore foods, with multiple feeding locations if needed. 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 8 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?
- Wild schooling behavior is not permission to keep a group in the minimum listed tank size.
- 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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