Acanthurus triostegus

Fiveband surgeonfish

Features
By Rex Gamoke

Geographic Range

Convict tangs are found throughout the Indo-Pacific region, as well as the eastern Pacific Ocean from the lower Gulf of California to Panama. They are also known as convict surgeonfish or Manini.

Habitat

Convict tangs are surgeonfish that prefer to occupy coral reefs, but are also found in tidepools and other nearshore habitats such as shallow, low current beach communities. They are tropical reef fish whose latitudinal range is 26ºN to 36ºS with a longitudinal range from 25ºE to 85ºW. Convict tangs are mainly found in temperatures ranging from 24-26ºC and at depths of 0-90 m.

Physical Description

Convict tangs have a pale body color varying from white/greenish-white to gray or even yellow. This background is overlaid with distinct, vertical black stripes, including one going through each eye. They are highly laterally compressed and have small scales, gill rakers, dorsal spines and anal spines. Their average length is 17.0 cm, with a maximum length of 27.0 cm.

Development

Convict tang eggs hatch into clear pelagic larvae. In Hawaiian populations it takes about 2.5 months for these planktonic larvae to develop into juveniles in a reef or tidepool; larvae typically adapt to their benthic surroundings within 24 hours. Initially, juveniles lack the vertical bars present in adults.

Reproduction

Convict tangs spawn in resident spawning aggregations. Spawning groups can be as large as tens of thousands of fish with subgroups of 10-20 fish, although pair spawning has also been observed. Research in Hawaii showed that individuals may migrate up to 2 km to reach spawning sites on the seaward side of a reef or in channels connecting lagoons to open ocean.

Convict tang populations near the equator can spawn at any time during the year, while populations elsewhere may only spawn seasonally (in Hawaii spawning occurs around full moons in February and March).

Convict tangs are broadcast spawners and provide no parental investment to offspring.

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

Convict tangs have a typical lifespan of 5-7 years in captivity. Their average lifespan in the wild is currently unknown.

Behavior

Convict tangs are often found in schools (large and small) but may also be found individually. While less territorial than other tangs, tank size is still an important consideration for those keeping this species. Convict tangs have been observed in the wild exhibiting tonic immobility (death feigning).

Home Range

There is currently no published information regarding the home range or territory size of Convict tangs.

Communication and Perception

Convict tangs are able to perceive their environments through a number of sensory pathways, including sight, olfaction, sound and vibrations (detected by their lateral lines). Information regarding which of these senses are important in intra- and interspecific communication is currently unavailable.

Food Habits

Convict tangs are herbivores, grazing on algae found on rocks and corals. Adaptations to their algivorous diet include mouths that are slightly downwardly-directed and flexible, comb-like teeth.

  • Plant Foods
  • algae

Predation

Convict tangs have been observed exhibiting tonic immobility, which may be a response to the presence of a predator. As with other surgeonfishes, they have sharp blades on either side of the tail; however, these blades are poorly developed in convict tangs and not typically used for defense. Instead, this species relies on traveling in large schools, as well as its disruptive color pattern, for protection. Although undoubtedly not a complete list of predators, convict tangs are known to be preyed upon by argus grouper, ash-colored conger eel, honeycomb grouper, cornet fish, and black-tail snapper. Eagle rays are also known to feed on convict tang gametes during spawning.

Ecosystem Roles

The grazing of convict tangs on algae helps keep algal populations in check. Convict tangs also host symbiotic unicellular organisms in their gut, including one of the largest known bacterial species ( Epulopiscium fishelsoni ). Convict tangs are host to endoparasitic nematodes and trematodes, as well as at least one ectoparasitic copepod species.

Mutualist Species
Commensal/Parasitic Species

Economic Importance for Humans: Positive

Convict tangs are part of the human diet in tropical regions. They are also sold in the aquarium trade.

Economic Importance for Humans: Negative

There have been reports of humans suffering from ciguatera poisoning after consuming convict tangs, although the species is generally considered safe to eat.

Conservation Status

Convict tangs currently have no special conservation status.

Other Comments

Genetic studies on Polynesian populations of convict tangs indicate that, despite the pelagic larval stage, most populations exhibit limited recruitment through dispersal.

The large bacterium Epulopiscium fishelsoni was first isolated from the gut of brown surgeonfish ( A. nigrofuscus ); similar morphotypes, collectively called "euplos", have since been found in other surgeonfish species, including convict tangs. Euplo morphotypes found in convict tangs are 20 times longer than they are wide, which is much longer and thinner than those found in other species of surgeonfish.

Encyclopedia of Life

Contributors

Rex Gamoke (author), Sierra College, Jennifer Skillen (editor), Sierra College, Jeremy Wright (editor), University of Michigan-Ann Arbor.

native range

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

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.

World Map

native range

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

tropical

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

saltwater or marine

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

pelagic

An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).

benthic

Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.

reef

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.

coastal

the nearshore aquatic habitats near a coast, or shoreline.

ectothermic

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

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.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

iteroparous

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).

seasonal breeding

breeding is confined to a particular season

year-round breeding

breeding takes place throughout the year

sexual

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

fertilization

union of egg and spermatozoan

external fertilization

fertilization takes place outside the female's body

oviparous

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

natatorial

specialized for swimming

motile

having the capacity to move from one place to another.

solitary

lives alone

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

visual

uses sight to communicate

tactile

uses touch to communicate

acoustic

uses sound to communicate

vibrations

movements of a hard surface that are produced by animals as signals to others

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

pet trade

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

food

A substance that provides both nutrients and energy to a living thing.

poisonous

an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).

herbivore

An animal that eats mainly plants or parts of plants.

References

Alwany, M., E. Thaler, M. Stachowitsch. 2005. Territorial behaviour of Acanthurus sohal and Plectroglyphidodon leucozona on the fringing Egyptian Red Sea reefs. Environmental Biology of Fishes , 72/3: 321-334. Accessed November 19, 2011 at http://www.springerlink.com/content/r74h276543486h60/ .

Arthur, J., S. Lumanlan-Mayo. 1997. Checklist of the parasites of fishes of the Philippines. FAO Fisheries TechnicalPaper , 369: 1-102. Accessed August 06, 2012 at http://www.fao.org/docrep/field/009/w6598e/W6598E00.htm#TOC .

Bergenius, M., M. McCormick, M. Meekan, D. Robertson. 2005. Environmental influences on larval duration, growth and magnitude of settlement of a coral reef fish. Marine Biology , 147/2: 291-300. Accessed October 26, 2011 at http://www.springerlink.com/content/q183w242824w4k55/ .

Bond, C. 1996. Biology of Fishes . Stamford, CT: Brooks/Cole.

Bresler, V., W. Montgomery, L. Fishelson, P. Pollak. 1998. Gigantism in a bacterium, Epulopiscium fishelsoni , correlates with complex patterns in arrangement, quantity, and segregation of DNA. Journal of Bacteriology , 180/21: 5601-5611. Accessed July 18, 2012 at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC107617/ .

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Eble, J., R. Toonen, B. Bowen. 2009. Endemism and dispersal: comparative phylogeography of three surgeonfishes across the Hawaiian Archipelago. Marine Biology , 156/4: 689-698. Accessed October 26, 2011 at http://www.springerlink.com/content/h17u480468634g92/ .

Education Department Waikiki Aquarium, 2012. "Marine Life Profile: Manini or Convict Tang" (On-line pdf). Waikiki Aquarium. Accessed July 17, 2012 at http://www.waquarium.org/_library/images/education/marinelifeprofiles/manini0909.pdf .

Fauvelot, C., S. Planes. 2002. Understanding origins of present-day genetic structure in marine fish: biologically or historically driven patterns?. Marine Biology , 141/4: 773-788. Accessed October 02, 2011 at http://www.springerlink.com/content/6923rtqgqhnfv7nu/ .

Fishelson, L. 1999. Polymorphism in gigantobacterial symbionts in the guts of surgeonfish (Acanthuridae: Teleostei). Marine Biology , 133/2: 345-351. Accessed November 18, 2011 at http://www.springerlink.com/content/8b407mf9ldvpbkfe/ .

Froese, R., D. Pauly. 2011. "FishBase, www.fishbase.org" (On-line). Accessed July 18, 2012 at http://www.fishbase.org/summary/Acanthurus-triostegus.html .

Halstead, B., P. Auerbach, D. Campbell. 1990. A colour atlas of dangerous marine animals . Ipswich, England: W.S. Cowell Ltd. Accessed July 18, 2012 at http://books.google.com/books?id=LIZfv6-_6X0C&pg=PA9&source=gbs_toc_r&cad=4#v=onepage&q=ciguatera&f=false .

Howe, J. 1992. Field observations of death feigning in the convict tang, Acanthurus triostegus (Linnaeus), with comments on the nocturnal color pattern in juvenile specimens. Journal of Aquariculture and Aquatic Sciences , 5/4: 13-15.

Kiflawi, M., A. Mazeroll. 2006. Female leadership during migration and the potential for sex-specific benefits of mass spawning in the brown surgeonfish ( Acanthurus nigrofuscus ). Environmental Biology of Fishes , 76/1: 19-23. Accessed November 18, 2011 at http://www.springerlink.com/content/e404r736x2574qv0/ .

Lecchini, D., R. Galzin. 2005. Spatial repartition and ontogenetic shifts in habitat use by coral reef fishes (Moorea, French Polynesia). Marine Biology , 147/1: 47-58. Accessed October 29, 2011 at http://www.springerlink.com/content/4h3w44ktbd86je0r/ .

Lewis, A. 1964. Caligoid copepods (Crustacea) of the Hawaiian islands: parasitic on fishes of the family Acanthuridae. Proceedings of the United States National Museum , 11/3482: 137-244.

Nakamura, Y., T. Shibuno, D. Lecchini, T. Kawamura, Y. Watanabe. 2009. Spatial variability in habitat associations of pre- and post-settlement stages of coral reef fishes at Ishigaki Island, Japan. Marine Biology , 156/11: 2413-2419. Accessed November 20, 2011 at http://www.springerlink.com/content/mt21663471706w38/ .

Planes, S., P. Borsa, R. Galzin, F. Bonhomme. 1994. Geographic structure and gene flow in the manini (convict surgeonfish, Acanthurus triostegus ) in the south-central Pacific. Pp. 113-122 in Genetics and evolution of aquatic organisms . London: Chapman & Hall. Accessed July 18, 2012 at http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_51-52/010019976.pdf .

Reebs, S. 2007. "Fishes feigning death" (On-line). How Fish Behave. Accessed November 20, 2011 at http://www.howfishbehave.ca/pdf/Feigning%20death.pdf .

Rigby, M., M. Adamson. 1997. Spirocamallanus species of French Poynesian coral reef fishes. Canadian Journal of Zoology , 75/8: 1270-1279. Accessed August 06, 2012 at http://www.nrcresearchpress.com/doi/abs/10.1139/z97-150?journalCode=cjz .

2012. "Convict Tang - Acanthurus triostegus" (On-line). Fish Lore. Accessed July 17, 2012 at http://www.fishlore.com/profile-convicttang.htm .

To cite this page: Gamoke, R. 2012. "Acanthurus triostegus" (On-line), Animal Diversity Web. Accessed {%B %d, %Y} at https://animaldiversity.org/accounts/Acanthurus_triostegus/

Last updated: 2012-17-04 / Generated: 2025-10-03 00:58

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