The pearlscale butterflyfish (''Chaetodon xanthurus''), also known as yellow-tailed butterflyfish, crosshatch butterflyfish or Philippines chevron butterflyfish is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae.

Description

Pearlscale butterflyfish can grow to a

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

of with no discernible differences between males and females. The body is pearly white and the scales have black edges, giving the sides a more cross-hatched pattern instead of the clear chevrons in related species. The hind parts are orangey-yellow, the base of the caudal fin is white. The head is darker than the body and bears the characteristic pattern of its lineage, consisting of vertical black eyestripes and a black white-rimmed crown spot.

Distribution

The Pearl scale butterflyfish is found on or around the reefs of the central

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 from Indonesia and the Philippines north to the Ryukyu Islands.

Ecology in the wild and the aquarium

Pearlscale butterflyfish are a diurnal species and usually found at depths below . They are found in clear coastal to outer reef slopes and drop-offs, often around ''

Acropora ''Acropora'' is a genus of small polyp stony coral in the phylum Cnidaria. Some of its species are known as table coral, elkhorn coral, and staghorn coral. Over 149 species are described. ''Acropora'' species are some of the major reef corals r ...

'' staghorn corals. These fish have a peaceful temperament and in the wild are found either alone, in pairs, or in small groups, however they are territorial towards similar-looking species and may harass them. Due to its attractive colors, the Pearlscale Butterflyfish is a well-known

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

fish. A 50-gallon aquarium is the minimum size recommended for them, with a water temperature of between about 74 and 80° F. Although they can be aggressive at times, they are delicate and peaceful tankmates are required for this fish to thrive in an aquarium. They may be compatible with other butterflyfishes that have a different color pattern, but there is no guarantee that their relationship will always be peaceful. When adding more than one to a tank they have to be added simultaneously, and lots of " live rock" with shelters available for them to hide helps to reduce stress. In the wild they feed on

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

, soft

coral polyp Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...

s and small

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

invertebrates, so therefore along with other coral-eating ''Chaetodon'' species they can wreak havoc on living corals in the aquarium. They should be fed a variety of foods that can include

mysid shrimp Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in ...

, brine shrimp, krill, spirulina and foods containing algae.

Systematics

''C. xanthurus'' is one of the "crowned" butterflyfishes. These form a group of largely

allopatric Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

species sharing the overall color pattern of dark forward-pointing chevrons on silvery hues, (usually) a black-and-white crown spot and yellow to red hindparts to a stunning degree; they differ in the exact combination of hues and some small pattern details. Other members of this lineage are the Atoll (''C. mertensii''), Eritrean (''C. paucifasciatus'') and

Seychelles butterflyfish The Seychelles butterflyfish (''Chaetodon madagaskariensis'') is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae. It is found in the Indian Ocean from eastern Africa (as far south as Port Elizabeth in ...

es (''C. madagaskariensis''), which are closer related among each other that any is to ''C. xanthurus''. The "crowned" ''Chaetodon'' are a clearly recognizable

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

, but their further relationships are otherwise less clear. They were often placed in the

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 ...

''Exornator'', or considered a distinct subgenus ''Rhombochaetodon''. According to various

DNA sequence DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

studies, some older and more singular lineages. These include species such as the Asian Butterflyfish ('' C. argentatus''), the

Blue-striped Butterflyfish The bluestripe butterflyfish or blue-striped butterflyfish (''Chaetodon fremblii'') is a species of butterflyfish (family Chaetodontidae) found in the waters surrounding the Hawaiian Islands. The fish is endemic to Hawaii where it is common on sha ...

('' C. fremblii'') and

Burgess' Butterflyfish Burgess' butterflyfish (''Chaetodon burgessi''), also known as the black & white butterflyfish or black-barred butterflyfish, is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae. It occurs in the wester ...

('' C. burgessi''). ''C. burgessi'' is in fact so peculiar that it was placed in a monotypic subgenus ''Roaops''. But recognition of this would probably result in several other small or monotypic subgenera becoming justified, and the older ''Rhombochaetodon'' would be the more conveniently apply to the entire

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...

. But the expanded group is of unclear relationships to species like the

Speckled Butterflyfish ''Chaetodon citrinellus'' is a species of butterflyfish (family Chaetodontidae). It is commonly known as the speckled butterflyfish or citron butterflyfish. It is found in the Indo-Pacific: the Red Sea, East Africa to the Hawaiian, Marquesan and ...

(''C. citrinellus'') and the

Four-spotted Butterflyfish The four-spotted butterflyfish or fourspot butterflyfish (''Chaetodon quadrimaculatus'') is a species of butterflyfish ( family Chaetodontidae) found in the Pacific Ocean from the Ryukyus, Ogasawara (Bonin) Islands and Taiwan to the Hawaiia ...

(''C. quadrimaculatus''). These might be members of the subgenus ''Exornator'' – the lineages around the

Spot-banded Butterflyfish The spot-banded butterflyfish or spotband butterflyfish (''Chaetodon punctatofasciatus'') is a species of marine ray-finned fish, a butterflyfish belonging to the family Chaetodontidae. It is from the western Pacific Ocean. It is found in the I ...

(''C. punctatofasciatus'') – and ''C. citrinellus'' certainly looks somewhat similar to these. Yet phylogenetically, their position towards ''Rhombochaetodon'' is unresolved, and ultimately it might be better to merge both ''Rhombochaetodon'' and ''Roaops'' in ''Exornator''. If the genus ''

Chaetodon ''Chaetodon'' is a tropical fish genus in the family Chaetodontidae. Like their relatives, they are known as "butterflyfish". This genus is by far the largest among the Chaetodontidae, with about 90 living species included here, though most migh ...

'' is split up, ''Exornator'' might become a subgenus of ''Lepidochaetodon'' or a separate genus.

References

External links

* {{DEFAULTSORT:Pearlscale Butterflyfish Chaetodon Fish described in 1857