Threadfin Butterflyfish

The threadfin butterflyfish is recognized by the thin dark lines crossing its white body at right angles, its yellow rear body and the black band covering its eye. In adults a long filament extends from the rear of the dorsal fin, with a black eyespot below it. While most butterflyfish adapt to the aquarium with difficulty, this species switches to prepared foods relatively easily. Specimens are wild-collected.

• At least 400 liters and 150 cm in length; rock structures and open swimming space.
• Salinity specific gravity 1.023–1.026, pH 8.1–8.4, temperature 24–27°C.
• Not reef-safe: It eats coral polyps, anemones, tube worms and zoanthids. It is also used to clean up Aiptasia, but the risk to corals is high.
• Suitable for fish-focused (FOWLR) aquariums.

Omnivorous. Frozen mysis, brine shrimp, chopped mussels and shrimp, foods containing seaweed. In the first days, a half-opened mussel stimulates the appetite. Small amounts 2–3 times a day.

Peaceful and active. It can be cantankerous towards its own species and other butterflyfish; in the wild it lives in pairs.

Good companions: Tangs, large angelfish, Heniochus, foxface, calm wrasses, cardinalfish.

Avoid: Reefs with corals and anemones, tube worms, fin-nipping triggerfish and pufferfish.