Not furry, but we like them anyway.

Aiptasia-eating Filefish

Acreichthys tomentosus

Also called Bristle-tail filefish, Bristle-tail leatherjacket

SpeciesShort profile

From Indo-West Pacific: Sri Lanka east through Indonesia to New Caledonia and Tonga, north to southern Japan1 2

At a glance the quick version

Length12 to 14 cm1 2 3

Sizesmall

Eats pest Aiptasia anemones

Master of camouflage

Small and peaceful

2 3

Looks how to spot one

Small, thin-bodied filefish with rough skin

A slim, flattened body in mottled green, brown and tan. It can change its colour, pattern and skin texture quickly to blend in with weed and rubble.2 3 4

Coloursgreenbrowntan3 4

Personality what they are like

Peaceful and somewhat shy, though curious. It rarely bothers other fish apart from its close relatives.3 4

Daily activity how busy a day looks

A calm swimmer that likes to hover among rockwork or gorgonians and peek out at its surroundings.4

Grooming and care the hands-on bits

Rated easy to moderate care. Often added to clean up Aiptasia anemones, but use caution in reef tanks since it may nip at soft and stony corals. Acclimate slowly.3 4 2

Home where they are happiest

A tank of at least 30 US gallons (about 115 L) with rockwork for shelter. Saltwater at 22 to 26 °C (72 to 78 °F), pH 8.1 to 8.4, specific gravity 1.020 to 1.025, dKH 8 to 12. Wild fish live on shallow reefs, seagrass and rubble at 2 to 15 m.3 1

Food basics what goes in the bowl

An omnivore. Feed small amounts several times a day: mysis, shaved shrimp, squid, scallop, soaked krill and frozen marine algae. Wild fish eat small bottom animals such as amphipods, worms and molluscs.3 4 1

Company who they like around

Generally solitary. Best kept as a single fish or with peaceful tankmates.1 3

The story where it all began

Linnaeus described the species in 1758. It became popular with reef keepers as a natural way to control Aiptasia, a common pest anemone in aquariums.1 2

Fun facts for the dinner table

1
It can change colour, pattern and even skin texture to hide.2
2
Reef keepers prize it for eating pest Aiptasia anemones.2
3
Wild fish live in shallow seagrass beds as well as on reefs.1
4
Despite its small size it is valued as part of a reef tank's clean-up crew.2

Recognised by the official bits

IUCN Red List: Least Concern (assessed 2015)1

The care rhythm Furry Diary remembers it for you

A typical home-care rhythm for a Aiptasia-eating Filefish. It is our own starting plan, not a vet's advice, and you can change every line in the app.

FeedingSmall amounts once or twice a dayevery day
Temperature checkevery day
Salinity checkevery week
Top-upTop up evaporation with fresh RO water, not salt waterevery day
Water testevery week
Water changeAbout 10 to 20% of the waterevery 2 weeks
Glass cleanevery week

Start a free diary

Valentini Puffer

Longhorn Cowfish

our little thank-you jar

Like what we are building? Buy us a coffee.

The breed atlas is free for everyone, with a source on every fact, and it will never show ads. If it helped you, a small tip keeps the research going. Any amount is lovely, and no is a perfectly fine answer too.

Leave a tip

Where this comes from

Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at support@furrydiary.app and we will fix it.

FishBase: Acreichthys tomentosus, Bristle-tail file-fish fishbase.seused for distribution, length, depth, habitat, diet, IUCN status, describer
Wikipedia: Acreichthys tomentosus en.wikipedia.orgused for other names, length, camouflage, Aiptasia control
LiveAquaria: Aiptasia Eating Filefish liveaquaria.comused for aquarium care, tank size, water parameters, temperament, diet, colours
Saltwaterfish.com: Aiptasia Eating Filefish saltwaterfish.comused for care level, temperament, behaviour, diet

Checked 2026-09-30. Text is written in our own words from these sources.