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Mimic Eibli Tang
Tangs · Acanthuridae

Mimic Eibli Tang

Acanthurus tristis

Juveniles have orange bars and a dark tail, resembling Eibli Angelfish. Adults lose much of the striped juvenile pattern and become pale brown with darker fins. This is a distinct species from the Lemonpeel Mimic Tang; the illustration shows its juvenile stage.

Care levelIntermediate

Can be strongly intolerant of other tangs with a similar shape. Adult appearance differs substantially from the juvenile.

Recommendation

Would you recommend this fish for a suitable saltwater aquarium?

125+ galRecommended tank
10 inchesAdult size
Semi-aggressive / territorialTemperament
Generally compatibleCoral safety

+ Why you’ll love them

  • Juveniles have orange bars and a dark tail, resembling Eibli Angelfish.
  • 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 125 US gallons or more with suitable swimming space.
  • Can be strongly intolerant of other tangs with a similar shape. Adult appearance differs substantially from the juvenile.
  • Requires a consistent feeding routine and stable water.
  • Has sharp tail spines; handle carefully.

Tank and habitat

Recommended volume
125 US gallons or larger; allow for stocking and layout.
Full-grown size
10 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
Can be strongly intolerant of other tangs with a similar shape. Adult appearance differs substantially from the juvenile.
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 varied suitable plant-rich preparations while watching access to grazing areas. 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 10 inches. Growth depends on the individual and conditions; juvenile purchase size should not determine the long-term aquarium. Orange juvenile bars fade as the fish matures; the adult is generally pale brown with darker, pale-edged fins.

Before you buy

Is this fish right for your tank?
Confirm Acanthurus tristis, expect the juvenile pattern to fade, and plan tang compatibility before purchase.
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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