Zoster Butterflyfish

Zoster Butterflyfish

The Zoster Butterflyfish (Hemitaurichthys zoster), also called the brown-and-white or black pyramid butterflyfish, is a wonderful exception to the usual butterflyfish rules. Boldly marked with a broad white wedge across a dark brown-to-black body, it is a mid-water plankton feeder rather than a coral-grazer — which makes it both hardy and, crucially, reef-safe. Peaceful and happiest in a group, a small shoal drifting and feeding above the rockwork is a striking sight in a reef aquarium.

For keepers who want a butterflyfish that can be trusted with corals, this is one of the very best choices.

Natural Habitat & Origin

Hemitaurichthys zoster is found in the Indian Ocean, where it gathers in aggregations over current-swept outer reef slopes, hovering in open water to feed on zooplankton drifting past. It is a social fish that lives and feeds in groups.

In the aquarium it wants open swimming space above the rock, good flow, and ideally the company of its own kind.

Care Requirements

Maintain stable marine conditions: salinity around 1.024–1.026, pH 8.1–8.4, and a temperature of about 24–26°C (75–79°F), with good flow. Reaching about 16 cm (6 inches) and best kept singly or in a small group, it suits a tank of around 340 litres (about 90 US gallons) or more with open water to school. It is hardier than most butterflyfish and usually settles well into a mature system.

Diet & Feeding

The Zoster Butterflyfish is a planktivorous carnivore, feeding on zooplankton in the wild — which is exactly why it leaves corals alone. It accepts aquarium foods readily: offer frequent small meals of frozen mysis and enriched brine shrimp, finely chopped seafood, and quality marine preparations with some algae content. Feed several small meals a day to suit its mid-water grazing.

Behavior & Temperament

This is a peaceful, sociable fish that mixes well in a calm community. It can be kept singly, as a pair, or in a small group in a large tank, where its shoaling behaviour shows to best effect. It rarely troubles other fish and spends much of its time feeding in open water.

Tank Mates

Good companions are other peaceful marine fish — tangs, peaceful wrasses, anthias, fairy wrasses, cardinalfish and similar. Avoid aggressive species that will bully it. Unusually for a butterflyfish, it is reef-safe: as a plankton feeder it leaves corals and ornamental invertebrates alone, making it one of the few butterflyfish suitable for a full reef.

Breeding

Hemitaurichthys zoster is a pelagic spawner with planktonic larvae and is not bred in the home aquarium. Trade specimens are wild-collected from the Indian Ocean.

Common Health Issues

The Zoster Butterflyfish is among the hardier butterflyfish but, like all marine fish, is susceptible to marine ich (Cryptocaryon irritans) and marine velvet (Amyloodinium ocellatum), particularly when stressed or newly imported. Quarantine new arrivals, keep water quality stable, provide good flow, and feed frequently. Given a peaceful tank and a mature system, it is one of the most approachable, reef-safe and rewarding butterflyfish for an intermediate keeper.