The Raccoon Butterflyfish (Chaetodon lunula), also known as the crescent-masked butterflyfish, lunule butterflyfish, halfmoon butterflyfish, moon butterflyfish, raccoon butterfly, raccoon, raccoon coralfish, and redstriped butterflyfish, is a species of marine ray-finned, a butterflyfish belonging to the family Chaetodontidae. It is found in the Indian Ocean and Pacific Ocean. pesce farfalla mezzaluna
Chaetodon lunula can reach a length of 20 cm. These large butterflyfishes have an oval outline, with a pattern of ascending oblique reddish stripes on the flanks and black and white bands over the face and eyes, similar to the “raccoon” mask (hence the common name). They show a black spot on the caudal peduncle and oblique yellow stripes behind the head. They have 10-14 dorsal spines and 3 anal spines. pesce farfalla mezzaluna
Chaetodon lunula is a nocturnal species that usually lives in small groups. Adults feed mainly on nudibranchs and small invertebrates, but also on algae and coral polyps. This species can be found widely throughout the tropical Indo-Pacific region (East Africa to the Hawaiian and Marquesan islands, north to southern Japan) and in the southeast Atlantic (South Africa). It is missing in the Red Sea. This species prefers seaward reefs and shallow reef flats of lagoon, at a depth of over 30 m.
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 five to seven years. It has been observed as a beneficial predator of Aiptasia and Majano sea anemones. They will eliminate this nuisance pest within a two- to six-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 to the decoration. In a confined environment, this species is prone to succumbing to “marine ich”, infection by the ciliate Cryptocaryon irritans.
(extract from Wikipedia)