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 In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

, a

butterflyfish The butterflyfish are a group of conspicuous tropical marine fish of the family Chaetodontidae; the bannerfish and coralfish are also included in this group. The approximately 129 species in 12 genera are found mostly on the reefs of the Atlant ...

belonging to the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Chaetodontidae. It is found in the Indian and Pacific Oceans.

Taxonomy

''Chaetodon lunula'' was first formally described as ''Pomacentrus lunula'' in 1802 by the french naturalist Bernard Germain de Lacépède (1756-1825) with the type locality given as "the Indian Ocean". It belongs to the large

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...

''Rabdophorus'' which might warrant recognition as a distinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

. In this group, its closest relative is probably the very similar Red Sea raccoon butterflyfish or diagonal butterflyfish, ''C. fasciatus''. Other close relatives appear to be the black butterflyfish, '' C. flavirostris''), Philippine butterflyfish, ''C. adiergastos'', and perhaps also the unusual redtail butterflyfish, ''C. collare''. Although the coloration of this group varies greatly, 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 "

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...

" mask, with a white space between the dark crown and eye areas.

Description

''Chaetodon lunula'' can reach a length of 20 cm (nearly 8 in). 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 "

" 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.

Biology

''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.

Distribution

This species can be found widely throughout the tropical

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region (East Africa to the Hawaiian and Marquesan islands, north to southern Japan) and in the southeast

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

(South Africa). Chaetodon lunula on Israeli stamp

Habitat

This species prefers seaward reefs and shallow reef flats of lagoon, at a depth of over 30 m.

In the aquarium

The raccoon butterflyfish is generally not aggressive towards other fish, with the exception of

lionfish ''Pterois'' is a genus of venomous marine fish, commonly known as lionfish, native to the Indo-Pacific. Also called firefish, turkeyfish, tastyfish, or butterfly-cod, it is characterized by conspicuous warning coloration with red, white, crea ...

and

triggerfish Triggerfish are about 40 species of often brightly colored fish of the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest species richness in the Indo-Pacific. ...

. In captivity, the typical lifespan of a raccoon butterflyfish is five to seven years. It has been observed as a beneficial

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

of ''

Aiptasia ''Aiptasia'' is a genus of a symbiotic cnidarian belonging to the class Anthozoa ( sea anemones, corals). ''Aiptasia'' is a widely distributed genus of temperate and tropical sea anemones of benthic lifestyle typically found living on mangrov ...

'' and ''

Majano Majano ( fur, Maian) is a ''comune'' (municipality) in the Italian region of Friuli-Venezia Giulia, located about northwest of Trieste and about northwest of Udine. Majano borders the following municipalities: Buja, Colloredo di Monte Albano, ...

sea anemone Sea anemones are a group of predation, predatory marine invertebrates of the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemones are classifi ...

s. 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 The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a ...

Cryptocaryon irritans ''Cryptocaryon irritans'' is a species of ciliates that parasitizes marine fish, causing marine white spot disease or marine ich (pronounced ''ick''). It is one of the most common causes of disease in marine aquaria. Taxonomy ''Cryptocaryon i ...

''.

References

External links

* {{Taxonbar, from=Q1759410 Chaetodon Fish of Hawaii