Matted Filefish (Acreichthys tomentosus) Care Guide

A small, unassuming filefish prized in the reef hobby for its appetite for aiptasia pest anemones. Its mottled green-brown coloration provides excellent camouflage among macroalgae.

Overview

Acreichthys tomentosus is a species in the family Monacanthidae. A small, unassuming filefish prized in the reef hobby for its appetite for aiptasia pest anemones. Its mottled green-brown coloration provides excellent camouflage among macroalgae. Individual results vary — some specimens eat aiptasia voraciously while others may ignore them entirely. Generally reef-safe but may occasionally pick at coral polyps.

Taxonomy

Family: Monacanthidae
Genus: Acreichthys
Scientific name: Acreichthys tomentosus
Other names: Bristletail Filefish, Aiptasia Eating Filefish
Origin: Indo-Pacific

Habitat

Distributed across the western Pacific from Indonesia, the Philippines and the Ryukyu Islands south to the Great Barrier Reef and east to Fiji. Inhabits seagrass beds, sponge gardens and coral-rubble flats at depths of 2-25 m. Specialised predator of Aiptasia anemones, which limits its compatibility with corals in reef aquariums.

Tank requirements

Minimum tank volume: 120 L
Temperature: 24-27 °C
pH: 8.1-8.4
GH: 8-12 °dGH
Water flow: moderate
Adult size: 7-10 cm
Lifespan: 3-6 years
Difficulty: intermediate

Diet

Classified as omnivore. Recommended feeding frequency: 2x daily. In captivity, offer a varied diet appropriate to the species — quality prepared foods supplemented with frozen or live items of suitable size.

Compatibility

Temperament: peaceful
Swimming level: middle
Compatible tank mates: Clownfish, Blue Chromis, Tangs, Peaceful Wrasses
Avoid with: Aggressive Fish, Other Filefish

Reef compatibility

Generally classified as reef-safe with caution: may opportunistically pick at small ornamental shrimps, sessile invertebrates or, in some individuals, polyps. Suitability depends on the specific reef stock.

Breeding

Breeding strategy: egg-depositor
Breeding difficulty: advanced