Chaetodontidae, or butterflyfishes, are among the most widely recognized coral reef fishes. Their vivid coloration and striking patterns make them popular in the aquarium trade, although some species are difficult to maintain in aquaria (see Economic Importance). The family contains 10 genera with 114 species, the majority in the genus Chaetodon. They occur mainly in tropical waters, most densely distributed in the Indo-West Pacific, but some occupy warm temperate waters (see Habitat). Members of this family vary considerably in terms of color, but all butterflyfishes share certain morphological traits such as a deep, laterally compressed body, ctenoid scales that extend onto the soft-rayed portions of the dorsal and anal fins, and jaws that may be slightly or extremely elongated (see Physical Description). Jaw shape and size correlates with the type of prey consumed; some butterflyfishes feed upon small invertebrates or algae, others solely on coral polyps (known as obligate corallivores), and still others upon zooplankton (see Food Habits). Butterflyfish are largely pair-forming, pelagic (in the water column) spawners (see Reproduction), and are unique among reef fishes in that the larvae pass through a stage termed tholychthys during which a bony sheath encases the head (see Development). As of 1994, five chaetodontid species were listed as vulnerable to extinction (see Conservation Status).
Butterflyfishes are primarily tropical, although some species can be found in temperate regions. Most species occur in the Indo- West Pacific, from Australia to Taiwan. Only four species occur in the eastern Pacific, and 13 species in the Atlantic.
Biogeographic Regions: palearctic (Native ); oriental (Native ); ethiopian (Native ); neotropical (Native ); australian (Native ); oceanic islands (Native ); indian ocean (Native )
Butterflyfishes are brightly-colored, often yellow or white, with darker contrasting markings that may conceal the eye. They, like some other reef fishes, are sometimes described as “poster-colored” due to their vivid coloration. They typically have a false eye spot near the back of the body, which may be an anti-predator adaptation (see Predation). These fishes are laterally compressed (very thin when viewed from the front) but deep-bodied, appearing almost circular from the side. Strongly sheathed dorsal, pelvic, and anal fin spines accentuate the disk-like body shape. The continuous or slightly notched dorsal fin contains six to 16 spines and 15 to 30 soft rays. The caudal fin is rounded and has 15 branched rays. The body is covered with small ctenoid scales that extend well onto the dorsal and anal fins. Butterflyfishes have small mouths filled with brushlike, close-set teeth. Their snouts are pointed, with the degree of elongation depending on the species and the type of food it consumes. Some, such as Forcipiger flavissimus, have extremely long jaws like tweezers that can grasp invertebrates from narrow crevices. Others, such as Chaetodon ornatissimus, have short jaws for nipping off live coral polyps. The jaws of some butterflyfishes can measure more than 25% of their body length. Butterflyfishes are, in general, sexually monomorphic (males and females look alike), although occasionally males have been found to be larger than females. Depending on the species, butterflyfishes range from nine to 30 cm in length. (Click here to see a fish diagram).
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
Butterflyfishes are a marine family occupying tropical to warm temperate waters. Some occur in the brackish water of estuaries and protected bays, commonly along steep parts of rocky reefs. They are most often found in shallow (less than 20 m) water near coral reefs, but some are deepwater dwellers descending to 200 m. Some occur in seagrass habitats, deep mudflats, or shallow lagoons. Juveniles of many species occupy different areas than adults, such as tidal pools, boulder reefs and shallow areas without coral. Some investigators hypothesize that butterflyfishes may have originally been pelagic, non-reef fishes that colonized coral reefs on two or more separate occasions.
Habitat Regions: temperate ; tropical ; saltwater or marine
Aquatic Biomes: benthic ; reef ; coastal
Other Habitat Features: estuarine
Generally benthic feeders, many butterflyfishes eat small invertebrates, sponges or polychaete worms. Some feed on zooplankton, and others exist exclusively on coral polyps. Another feeding method is scraping the surface of live coral to obtain algae, attached invertebrates, and mucus from the coral. Some are herbivores, grazing on the filamentous algae covering coral reefs, and a few eat seagrasses and algae on reef flats. Butterflyfishes have long snouts, with the degree of elongation depending on the species and the type of food it consumes. Some, such as Forcipiger flavissimus, have extremely long jaws like tweezers that can grasp invertebrates from narrow crevices. Others, such as Chaetodon ornatissimus, have short jaws for nipping off live coral polyps. The jaws of some butterflyfishes can measure more than 25% of their body length.
Primary Diet: carnivore (Eats non-insect arthropods); herbivore ; omnivore ; planktivore
Butterflyfishes, like many other reef fishes, have coevolved with other organisms in their environment. Benthic invertebrates on the reef have developed heavy armor, spines, toxins, and adherence to the substrate, and butterflyfishes have evolved a variety of jaw forms that allow them to penetrate narrow crevices, reach exposed parts of invertebrates, or nip off coral polyps. The herbivorous members of the family have an impact as well, for their grazing of algae is important for the well-being of the reef. They, and other herbivorous reef fishes, keep algae that might otherwise smother the coral cropped to a mat one to two mm thick.
Most butterflyfishes have a dark band obscuring the eye, and often have a false eye spot in contrasting colors near the tail. These two attributes may confuse predators. The ocelli, or eye spots, may reduce damage from fin-biting predators by mimicking the head. Another possibility is that the ocelli are a signal to help maintain cohesion in shoaling groups.
Known prey organisms
This list may not be complete but is based on published studies.
Life History and Behavior
Daytime feeders, butterflyfishes use vision to find their prey. Pairs also communicate visually; if a pair becomes separated, one may swim upwards in a display that helps the two locate each other. During agonistic encounters between members of Chaetodon lunula, the fishes’ yellow colors intensify and their countershading fades, a visual signal of aggressive interaction.
Communication Channels: visual
Perception Channels: visual ; tactile ; chemical
Butterflyfish eggs are spherical, buoyant, and transparent, and, for those species observed, hatch in 28 to 30 hours. A drop of oil behind the yolk suspends the newly-hatched fish upside down just beneath the surface. By the time an individual reaches 5.5 mm, it enters the tholichthys larval stage, unique among reef fishes, in which bony armor covers the head. The sheath of thin bony plates extends beyond the head to form spines dorsally and ventrally. The shape and form of the plates and spines varies from species to species, but in general tholichthys larvae are silver-colored, deep bodied, and laterally compressed. These pelagic larvae may be planktonic for two or more months. The bony plates are absorbed within a few weeks after the fish settle to the bottom. The larvae settle at night and transform quickly into juveniles. In many species of butterflyfish, juveniles have a color pattern that is quite distinct from their adult form. Butterflyfishes most likely reach sexual maturity when they are about a year old.
No specific information was found on butterflyfish longevity, but it can be surmised that most species live at least three years and probably longer, since they reach sexual maturity after about a year and many pairs are reported to be stable for at least three years.
Butterflyfishes, according to existing research, are characteristically monogamous and pair-forming. Occasionally pairs have been observed accompanied by a juvenile, which allows for the possibility that juveniles may be ambisexual, or able to mature into male or female depending on which sexually mature fish in a pair dies and needs to be replaced. However, there is no definitive research indicating whether this actually occurs or not. In many species pairs are stable for at least three years, and some butterflyfishes may pair for life.
Mating System: monogamous
Research on butterflyfish reproductive behavior has been limited to a few species, but available information suggests that tropical spawning activity peaks in winter and early spring, while species in more temperate areas spawn in midsummer. Some groups spawn throughout the year. Spawning usually occurs at dusk. Females are often visibly distended with eggs when they are ready to spawn. The male swims behind and below the female, and here he uses his snout to nudge her abdomen. Spawning pairs in Prognathodes aculeatus have been observed chasing each other around a large sponge. A common element among species seems to be an ascent into the water column to release gametes (eggs and sperm). After a few “false starts” the pair rises up into the water, the male’s snout against the female’s abdomen. They release a white cloud of gametes and rush back toward the bottom. In some species other males have been seen dashing over to a spawning pair to add their own sperm to the cloud.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
No specific information on parental care in Chaetodontidae was found. However, it is unlikely that butterflyfishes care for their eggs or young, because eggs are released and fertilized in the water column 10 or 15 m above the fishes’ normal habitat, and the pelagic tholichthys larvae are well-equipped with their own protective armor.
Parental Investment: no parental involvement
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimens with Sequences:1193
Specimens with Barcodes:959
Species With Barcodes:91
As of 1994 there were five species of butterflyfish listed as vulnerable to extinction, all in the genus Chaetodon. Their vulnerability is based on the limited spaces in which they are found, making them extremely susceptible to human activities in those areas.
Relevance to Humans and Ecosystems
No specific information was found concerning any negative impacts to humans.
Butterflyfishes are one of the most popular tropical fishes with divers and aquarists. Some do well in aquaria but those that eat only coral are almost impossible to keep successfully.
Positive Impacts: pet trade
The butterflyfishes are a group of conspicuous tropical marine fish of the family Chaetodontidae; the bannerfishes and coralfishes are also included in this group. The approximately 120 species in 10 genera are found mostly on the reefs of the Atlantic, Indian, and Pacific Oceans. A number of species pairs occur in the Indian and Pacific Oceans, members of the huge genus Chaetodon.
Butterflyfishes look like smaller versions of angelfish (Pomacanthidae), but unlike these, lack preopercle spines at the gill covers. Some members of the genus Heniochus resemble the Moorish idol (Zanclus cornutus) of the monotypic Zanclidae. Among the paraphyletic Perciformes, the former are probably not too distantly related to butterflyfish, whereas the Zanclidae seem far less close.
Description and ecology
Butterflyfishes mostly range from 12 to 22 cm (4.7 to 8.7 in) in length. The largest species, the lined butterflyfish and the saddle butterflyfish, C. ephippium, grow to 30 cm (12 in). The common name references the brightly coloured and strikingly patterned bodies of many species, bearing shades of black, white, blue, red, orange, and yellow. Other species are dull in colour. Many have eyespots on their flanks and dark bands across their eyes, not unlike the patterns seen on butterfly wings. Their deep, laterally narrow bodies are easily noticed through the profusion of reef life. The conspicuous coloration of butterflyfishes may be intended for interspecies communication. Butterflyfish have uninterrupted dorsal fins with tail fins that may be rounded or truncated, but are never forked.
Generally diurnal and frequenting waters less than 18 m (59 ft) deep (though some species descend to 180 m (590 ft)), butterflyfishes stick to particular home ranges. These coralivores are especially territorial, forming pairs and staking claim to a specific coral head. Contrastingly, the zooplankton feeders form large conspecific groups. By night, butterflyfish hide in reef crevices and exhibit markedly different coloration.
Their coloration also makes them popular aquarium fish. However, most species feed on coral polyps and sea anemones. Balancing the relative populations of prey and predator is complex, leading hobby aquarists to focus on the few generalists and specialist zooplankton feeders.
Butterflyfishes are pelagic spawners; that is, they release many buoyant eggs into the water, which become part of the plankton, floating with the currents until hatching. The fry go through a tholichthys stage, wherein the body of the postlarval fish is covered in large, bony plates extending from the head. They lose their bony plates as they mature. Only one other family of fish, the scats (Scatophagidae) express such an armored stage.
The family name derives from the Ancient Greek words χαιτέ, chaite ("hair") and οδοντος, odontos ("tooth"). This is an allusion to the rows of brush-like teeth found in their small, protrusible mouths.
Taxonomy, systematics and evolution
The Chaetodontidae can be, but are not usually, divided into two lineages that arguably are subfamilies. The subfamily name Chaetodontinae is a little-used leftover from the period when the Pomacanthidae and Chaetodontidae were united under the latter name as a single family. Hence, Chaetodontinae is today considered a junior synonym of Chaetodontidae. In any case, one lineage of Chaetodontidae (in the modern sense) contains the "typical" butterflyfishes around Chaetodon, while the other unites the bannerfish and coralfish genera. As the Perciformes are highly paraphyletic, the precise relationships of the Chaetodontidae as a whole are badly resolved.
Before DNA sequencing, the taxonomy was confused about whether to treat these as species or subspecies. Also, numerous subgenera have been proposed for splitting out of Chaetodon, and it is becoming clear how to subdivide the genus if that is desired.
The fossil record of this group is marginal. Their restriction to coral reefs means their carcasses are liable to be dispersed by scavengers, overgrown by corals, and any that do fossilize will not long survive erosion. However, Pygaeus, a very basal fossil from the mid- to late Eocene of Europe, dates from around the Bartonian 40-37 million years ago (Mya). Thus, the Chaetodontidae emerged probably in the early to mid-Eocene. A crude molecular clock in combination with the evidence given by Pygaeus allows placement of the initial split between the two main lineages to the middle to late Eocene, and together with the few other fossils, it allows the deduction that most living genera were probably distinct by the end of the Paleogene 23 Mya.
The bannerfish-coralfish lineage can be further divided in two groups; these might be considered tribes, but have not been formally named. Genera are listed in order of the presumed phylogeny, from the most ancient to the youngest:Froese, Rainer, and Daniel Pauly, eds. (2013). "Chaetodontidae" in FishBase. February 2013 version.
Bannerfish/coralfish lineage 1:
Bannerfish/coralfish lineage 2:
The "typical" butterflyfishes may eventually come to contain more genera; see Chaetodon:
Copperband butterflyfish, Chelmon rostratus
The enigmatic Johnrandallia nigrirostris
Sunburst butterflyfish, (sometimes placed in Lepidochaetodon)
Bluelashed butterflyfish, Chaetodon bennetti (sometimes placed in Megaprotodon)
- Pratchett, Morgan S. & Berumen, Michael L. & Kapoor, B.G. [Editors] : Biology of Butterflyfishes. CRC Press, 2014. ISBN 978-1-4665-8290-3
|Wikimedia Commons has media related to Chaetodontidae.|
- Fessler, Jennifer L. & Westneat, Mark W. (2007): Molecular phylogenetics of the butterflyfishes (Chaetodontidae): Taxonomy and biogeography of a global coral reef fish family. Mol. Phylogenet. Evol. 45(1): 50–68. doi:10.1016/j.ympev.2007.05.018 (HTML abstract)
- FishBase : Family Chaetodontidae – Butterflyfishes. Retrieved 2008-SEP-02.
- Hsu, Kui-Ching; Chen, Jeng-Ping & Shao, Kwang-Tsao (2007): Molecular phylogeny of Chaetodon (Teleostei: Chaetodontidae) in the Indo-West Pacific: evolution in geminate species pairs and species groups. Raffles Bulletin of Zoology Supplement 14: 77-86. PDF fulltext
- Sepkoski, Jack (2002): [Chaetodon]. In: A compendium of fossil marine animal genera. Bulletins of American Paleontology 364: 560. HTML database excerpt
To request an improvement, please leave a comment on the page. Thank you!