Mauritius Triggerfish

Mauritius Triggerfish

The Mauritius Triggerfish (Rhinecanthus cinereus) is a robust, characterful member of the Picasso-trigger group, marked with bold lines and patterning across a grey-brown body. Like its relatives it is hardy, intelligent and full of personality — a fish that quickly learns to recognise its keeper and beg for food. It is, however, a true triggerfish in temperament and diet: aggressive, powerful, and an enthusiastic crusher of hard-shelled invertebrates.

It makes an engaging centrepiece for a robust fish-only aquarium, but is unsuitable for a reef or a peaceful community.

Natural Habitat & Origin

Rhinecanthus cinereus is found in the Indian Ocean, where it lives over coral and rocky reefs and rubble zones, hunting crustaceans, molluscs, urchins and other hard-shelled prey. It shelters in holes and crevices, wedging itself in with its dorsal trigger spine when threatened.

In the aquarium it wants substantial, securely arranged rockwork with caves to retreat into, plus open space to patrol, and a sand bed it can rearrange.

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). Reaching about 25 cm (10 inches), it needs a large tank of around 450 litres (about 120 US gallons) or more with robust, stable rockwork it cannot easily topple. It is exceptionally hardy and long-lived given good water quality.

Diet & Feeding

The Mauritius Triggerfish is a carnivore built to crush hard-shelled prey. Offer a varied meaty diet of shell-on shrimp, krill, mussel, clam, squid and similar foods, along with quality marine pellets — the hard items help keep its ever-growing teeth worn down. Feed once or twice a day; it is a powerful, enthusiastic feeder.

Behavior & Temperament

This is an aggressive, territorial fish, particularly as it matures, and it will dominate or harass smaller and more timid tankmates. It is best kept with robust companions in a large tank, or even as a solitary "wet pet." It actively rearranges rock and substrate, so aquascaping must be secure. Handle with care — triggers can bite.

Tank Mates

House it only with large, robust fish able to withstand its temperament — tangs, large wrasses, other triggers (with caution and space) and similar. Avoid small, timid or slow fish. It is not reef-safe: it will eat ornamental shrimp, crabs, snails and other invertebrates and may damage corals, so it belongs in a fish-only or fish-only-with-live-rock system.

Breeding

Rhinecanthus cinereus is a pelagic spawner and is not bred in the home aquarium; trade specimens are wild-collected.

Common Health Issues

The Mauritius Triggerfish is among the hardier marine fish, but it can still contract marine ich (Cryptocaryon irritans) or marine velvet (Amyloodinium ocellatum) under stress. Quarantine new arrivals, keep water quality stable, and provide secure rockwork. Mindful of its aggression, size and appetite for invertebrates, it is otherwise a tough, long-lived and engaging fish for a robust fish-only marine aquarium.