Raccoon Butterflyfish

Chaetodon lunula

Also known as Crescent-masked Butterflyfish, Halfmoon Butterflyfish, Lunule Butterflyfish

SaltwaterFish

Care at a glance

Temperature
75–81°F (24–27°C)
pH
8.1–8.4
Adult size
7.9 in (20 cm)
Minimum tank
106 gal (400 L)
Temperament
Mostly peaceful
Social behavior
Solitary
Swim level
Middle
Difficulty
Medium
Breeding
No record
Rarity
Common
Reef safe
Not reef safe
Origin
Indo-Pacific and Red Sea reefs, from East Africa to Hawaii and the Marquesas, south to Lord Howe Island
Family
Chaetodontidae

Overview

Not reef safe: it is one of the more food-driven butterflyfish and will pick at soft corals, large-polyp stony corals, anemones, tubeworms, and clam mantles, so it belongs in a fish-only or fish-only-with-live-rock system rather than a reef tank. It can be a bit more assertive at feeding time than other butterflyfish and may squabble with its own kind unless a pair is introduced together, but it otherwise mixes well with similarly sized tankmates. It is a strong eater once settled, taking mysis, chopped seafood, marine pellets, and algae-based foods, though newly imported fish sometimes need a few quiet, dimly lit days before they start feeding on their normal nocturnal schedule.

In the wild

Found across the Indo-Pacific and Red Sea from East Africa to Hawaii and the Marquesas, north to Japan and south to Lord Howe Island, on lagoon and seaward reefs where it shelters under coral ledges and in caves by day. It is mostly nocturnal in the wild, becoming most active around dusk, so it should be given plenty of rockwork with caves and overhangs to retreat into during the day. It also needs a well-established tank, since it is sensitive to copper-based medications and poor water quality. A tank of at least 400 litres (106 US gal) suits a single fish.

Good to know

Named for the black bandit-mask marking across its eyes, which resembles a raccoon's face, paired with a black crescent edged in white just behind it, the marking that gives the species its name lunula, or little moon. It reaches about 20 cm and, like many nocturnal reef fish, can shift into a duller, blotchy night pattern that helps it blend into the reef while it rests.

Did you know

Its nocturnal habits are strong enough that new arrivals often hide through the first several days in a tank and only come out to feed as the lights dim, which can look like a sick or stressed fish when it is really just running on a reef-appropriate schedule.

Appears in

Saltwater fish · FOWLR fish

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