Family : Chaetodontidae
Text © Giuseppe Mazza
English translation by Mario Beltramini
The Raccoon butterflyfish (Chaetodon lunula Lacepède, 1802) belongs to the class of the Osteichthyes, the bony fishes, to the Actinopterygii, the ray-finned fishes, to the vast order of Perciformes and to the colorful family of Chaetodontidae.
The name of the genus Chaetodon comes from the Greek “χαίτη” (khaite) = hair and “ὀδούς” (odous) = tooth, due to the “bristle-shaped teeth”.
The name of the species lunula comes from the Latin “luna” = moon, night, therefore, “small moon”, with reference to the black crescent it has on the eyes, followed by an analogous white pattern, and maybe also due to the fact that it is a nocturnal butterflyfish.
This characteristic black band on the eyes explains also the Italian, English and French name, of Raccoon butterflyfish.
It has a very vast distribution in the Indo-Pacific. We find it from South Africa, Madagascar, East Africa and Somalia up to the Maldives, India, Sri Lanka, Thailand, Australia, Indonesia, New Guinea, Micronesia, New Caledonia, Philippines, Taiwan, and China up to southern Japan.
Eastwards, it reaches the Marquesas, Ducie Island, Hawaii and the Galapagos; southwards, Lord Howe and Easter islands.
It lives in the atolls and on the border of the madreporic formations up to 30 m of depth.
The Raccoon butterflyfish can reach the 20 cm. The body is flat, more or less oval, with robust snout, slightly pointed.
The dorsal fin has 10-14 spiny rays and 20-25 soft; the anal has 3 spiny rays and 17-20 soft; the ventral ones 1 spiny ray and 5 soft; the pectoral are unarmed, with 14-17 rays, and the caudal is more or less blunt.
Yellow is the background colour. The wide carnivalesque black band hiding the eyes is followed by a white band and then by two black triangles pointing towards the back.
There is also a showy black spot on the caudal peduncle, which extends like an upside down comma on the back. The higher part of the sides, dark, breaks in direction of the belly into reddish lines ending in small dots.
The caudal fin, after the translucent part, exhibits a dark orange band which is resumed by the edge of the dorsal and anal ones. It is preceded, in the yellow zone by an elegant pattern with orange small dots, like those under the operculum.
The Raccoon butterflyfish lives in pairs or small schools.
It mainly nourishes of nudibranch molluscs and of tubicolous polychaetes, without ignoring the crustaceans, the small benthic organisms and the algae. The polyps of madrepore enter only marginally its alimentary diet.
After the fecundation, the eggs are entrusted to the currents.
The populations are not at risk because they may double in less than 15 months, the diet is varied, and the fishing vulnerability index is very low, marking just 10 on a scale of 100.
Pomacentrus lunula Lacepède, 1802; Chaetodon biocellatus Cuvier, 1831; Tetragonoptrus biocellatus Cuvier, 1831.