Chaetodon aurigaCross-stripe butterfly(Also: Diagonal butterflyfish; Whip butterflyfish)

Geographic Range

Threadfin butterflyfish are found throughout the Indian and Pacific Oceans. They are found in the Red Sea and the coast of eastern Africa, off the coasts of Australia and New Guinea, east to the Hawaiian, Marquesan, and Ducie islands, as far north as southern Japan, and south to the Lord Howe and Rapa islands. (Capuli, 2006; Nelson, 1984; Steene, 1977)


Threadfin butterflyfish are found in tropical coral reef habitats (Nelson 1984; Herald 1975; Jobling 1907). Although they are usually found where there is abundant coral, they are occasionally found in areas with sparse coral as well (Steene 1977). Chaetodon auriga are found at water depths between 1 and 35 meters (Capuli, 2006). (Capuli, 2006; Herald, 1962; Jobling, 1995; Nelson, 1984; Steene, 1977)

  • Range depth
    1 to 35 m
    3.28 to 114.83 ft

Physical Description

Threadfin butterflyfish are small, boldy colored fish (Findley and Findley 1985). They have a dark band running across the eye from the top of the head to the jaw, and a dark eyespot on the posterior part of the body (Nelson 1984). They have black lines and a yellow coloration on the posterior part of the body. They have broad, laterally compressed bodies and elongated snouts with small, sharp teeth (Moyle and Cech 2000). Adults can reach up to 23 cm (Steene 1977). Although young have patterns similar to adults, adults have a long filament extending from their dorsal fin (Steene 1977). (Findley and Findley, 1985; Moyle and Cech, 2000; Nelson, 1984; Steene, 1977)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    23 (high) cm
    9.06 (high) in


Butterflyfish release eggs into the water column, which are externally fertilized (Hourigan 1989). Embryos hatch approximately 30 days after spawning and the larvae then spend about 40 days floating in the water column as plankton before they metamorphose into juveniles (Hourigan 1989). (Hourigan, 1989)


Chaetodon auriga are monogamous, they mate with one partner and maintain this partnership for many years (Jobling 1995; Paxton and Eschmeyer 1998; Roberts and Ormond 1992). Low rates of adult mortality enable these monogamous relationships to last for many breeding seasons. However, if an individual loses a mate, they will find another (Roberts and Ormond 1992; Hourigan 1989) (Hourigan, 1989; Jobling, 1995; Paxton and Eschmeyer, 1998; Roberts and Ormond, 1992)

Female C. auriga release hundreds of thousands of eggs at a time (Hourigan 1989). Threadfin butterflyfish spawn frequently throughout their long breeding seasons (Roberts and Ormond 1992). They can be sexually mature at sizes of 13 cm (Capuli, 2006). (Hourigan, 1989; Jobling, 1995; Paxton and Eschmeyer, 1998; Roberts and Ormond, 1992)

  • Breeding interval
    Threadfin butterflyfish breed frequently. Factors influencing breeding frequency are not known.
  • Breeding season
    Threadfin butterflyfish may breed throughout the year.
  • Average time to hatching
    30 days

There is little information available on parental investment of Chaetodon auriga, however other species of butterflyfish do not invest in parental care (Roberts and Ormond, 1992). Once the eggs are fertilized in the water column, there is no further parental involvement. (Capuli, 2006; Roberts and Ormond, 1992)

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning
    • protecting
      • female


There is little information known about the lifespan of butterflyfish.


Threadfin butterflyfish are found in pairs, but are sometimes found singly or in large feeding groups (Steene 1977). Threadfin butterflyfish use their tubular snout to poke into coral holes and crevices in order to find prey (Norman 1975). They can also feed by scraping the surface of coral (Moyle and Cech 2000). They are active during the day and are non-migratory. (Capuli, 2006; Moyle and Cech, 2000; Norman, 1975; Steene, 1977)

Home Range

There is no information on home range in threadfin butterflyfish.

Communication and Perception

Threadfin butterflyfish are visual predators, and they use their appearance to fool potential predators. Little additional information is available on how they communicate with one another (Nelson 1984). (Nelson, 1984)

  • Communication Channels
  • visual

Food Habits

Chaetodon auriga are benthic feeding fish that feed mostly on plankton (Pratchett 2001). However, they are omnivorous, and also feed on coral polyps, algae, shrimp, gastropods, nemertime worms, and polychaetes (Steene 1977). Threadfin butterflyfish have elongated snouts, with small protractile mouths that are filled with many small, sharp teeth (Moyle and Cech 2000; Herald, 1962 Jordan, 1907). They are able to use their elongated snouts in order to scrape the surface of coral to obtain algae and other small prey (Moyle and Cech 2000). (Herald, 1962; Jordan, 1907; Moyle and Cech, 2000; Pratchett, et al., 2001; Steene, 1977)

  • Animal Foods
  • mollusks
  • aquatic or marine worms
  • aquatic crustaceans
  • cnidarians
  • zooplankton


There are few documented predators of threadfin butterflyfish (Jordan 1907). Their spiny fins and quick speed make them difficult prey (Norman 1975; Jordan, 1907). Threadfin butterflyfish have mechanisms in order to deter and avoid potential predators. The dark bands over their eyes, as well as the posterior eyespot are probably mechanisms to confuse potential predators, making their tails seem to be their head and their head seem to be a tail (Nelson 1984). Other butterflyfish species have been reported swimming short distances tail first, and then rapidly swimming off in the opposite direction in order to confuse and escape potential predators (Norman 1975). (Jordan, 1907; Nelson, 1984; Norman, 1975)

Ecosystem Roles

Butterflyfish are dependent on coral reefs to obtain much of their food. The number of butterflyfish in an area is largely dependent on the amount of coral in a particular reef ecosystem (Ohman et al. 1998). In addition, butterflyfish are important in reducing the amount of algae that accumulates on coral (Moyle and Cech 2000). Butterflyfish and their eggs and larvae are important food items for marine predators. (Moyle and Cech, 2000; Ohman, et al., 1998)

Economic Importance for Humans: Positive

It may be possible to use butterflyfish, such as threadfin butterflyfish as bio-indicators in order to monitor coral reef ecosystems (Brokovich and Baranes 2005; Ohman 1998). Chaetodon auriga are also kept in aquaria as pets. (Brokovich and Baranes, 2005; Ohman, et al., 1998)

  • Positive Impacts
  • pet trade
  • research and education

Economic Importance for Humans: Negative

Chaetodon auriga are not known to negatively affect humans.

Conservation Status

Chaetodon auriga is not threatened at this time. However, it is believed that the density of butterflyfish correlates with the amount of live coral in a particular region. If reef habitats are destroyed, this will threaten butterflyfish populations (Ohman et al. 1998). (Ohman, et al., 1998)


Tanya Dewey (editor), Animal Diversity Web.

Alison Rauss (author), University of Michigan-Ann Arbor, Kevin Wehrly (editor, instructor), University of Michigan-Ann Arbor.


Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


uses smells or other chemicals to communicate


the nearshore aquatic habitats near a coast, or shoreline.

  1. active during the day, 2. lasting for one day.

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body


union of egg and spermatozoan


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


Having one mate at a time.


having the capacity to move from one place to another.


specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.


an animal that mainly eats all kinds of things, including plants and animals


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.


photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)


structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


associates with others of its species; forms social groups.


uses touch to communicate


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


uses sight to communicate

year-round breeding

breeding takes place throughout the year


animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)


Brokovich, E., A. Baranes. 2005. Community structure and ecology of butterflyfishes (Chaetodontidae) in the Gulf of Aqaba (northern Red Sea). Aquatic Conservation: Marine and Freshwater Ecosystems, 15: S45-S58.

Capuli, E. 2006. "Chaetodon auriga, Threadfin butterflyfish" (On-line). Fishbase. Accessed November 20, 2006 at

Findley, J., M. Findley. 1985. A search for pattern in butterfly fish communities. American naturalist, 126/6: 800-816.

Herald, E. 1962. Living fishes of the world. Garden City, N.Y.: Doubleday.

Hourigan, T. 1989. Environmental Determinants of Butterflyfish social systems. Environmental Biology of Fishes, 25/1-3: 61-78.

Jobling, M. 1995. Environmental biology of fishes. London, New York: Chapman & Hall.

Jordan, D. 1907. Fishes. New York: Holt and Company.

Moyle, P., J. Cech. 2000. Fishes: an introduction to ichthyology. New Jersey: Prentice Hall.

Nelson, J. 1984. Fishes of the world. New York: Wiley.

Norman, J. 1975. A history of fishes. New York: Wiley.

Ohman, M., A. Rajasuriya, S. Svensson. 1998. The use of butterflyfishes (Chaetodontidae) as bio-indicators of habitat structure and human disturbance. AMBIO, 27/8: 708-716.

Paxton, J., W. Eschmeyer. 1998. Encyclopedia of fishes. San Diego, California: Academic Press.

Pratchett, M., N. Gust, G. Goby, S. Klanten. 2001. Consumption of coral propagules represents a significant trophic link between corals and reef fish. Coral Reefs, 20: 13-17.

Roberts, C., R. Ormond. 1992. Butterflyfish social-behavior, with special reference to the incidence of territoriality-a review. Environmental Biology of Fishes, 34/1: 79-93.

Steene, R. 1977. Butterfly and Angelfishes of the World Volume 1. New York, Toronto, Chichester, Brisbane: Wiley-Interscience Publication.