Fish o’ the day | Raccoon Butterfly

Posted by gerard on December 1, 2008 under Saltwater Fish | 3 Comments to Read

The Raccoon Butterflyfish (Chaetodon lunula) is also known as the Crescent-masked Butterflyfish or the Lunule Butterflyfish, is a species of butterflyfish (family Chaetodontidae). It is found in the Indo-Pacific region from East Africa to Ducie, the Hawaiian and the Marquesas Islands, north to southern Japan, south to Lord Howe Island and Rapa Iti, and also in the southeast Atlantic around East London, South Africa. Its length is up to 20 cm (nearly 8 in).

It belongs to the large subgenus Rabdophorus which might warrant recognition as a distinct genus. In this group, its closest relative is probably the very similar Red Sea Raccoon Butterflyfish or Diagonal Butterflyfish (C. lunula). Other close relatives appear to be the Black Butterflyfish (C. flavirostris), Philippine Butterflyfish (C. adiergastos), and perhaps also the unusual Red-tailed Butterflyfish (C. collare). Although the coloration of this group varies quite a lot, they are all largish butterflyfishes with an oval outline, and most have a pattern of ascending oblique stripes on the flanks. Except in the Red-tailed Butterflyfish, there is at least a vestigial form of the “racoon” mask, with a white space between the dark crown and eye areas.

The raccoon butterflyfish is a nocturnal species that is usually found in pairs or small groups in warm, shallow reef flats of lagoon and seaward reefs, at depths down to 30 m. Juveniles occur among rocks of inner reef flats and in tide pools. Adults feed mainly on nudibranchs, tubeworm tentacles, and other benthic invertebrates, algae and coral polyps. Reproduction is oviparous, with pairs forming during breeding.

The raccoon butterflyfish is generally not aggressive towards other fish, with the exception of lionfish and triggerfish. In captivity, the typical lifespan of a Raccoon Butterflyfish is 5 to 7 years. It has been observed as a beneficial predator of Aiptasia and Majano sea anemones. They will eliminate this nuisance pest within a 2- to 6-week period depending on the anemone population and size of the tank; however, they will eagerly feed on any soft corals and may cause more harm than good for the decoration. In a confined environment, this species is prone to succumbing to “marine ich”, infection by the ciliate Cryptocaryon irritans.

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