Cross Stripe Butterfly

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).

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).

Range length: 23 (high) cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

There is little information known about the lifespan of butterflyfish.

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).

Communication Channels: visual

Perception Channels: visual ; tactile ; chemical

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).

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

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).

Development - Life Cycle: metamorphosis

Chaetodon auriga are not known to negatively affect humans.

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.

Positive Impacts: pet trade ; research and education

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.

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).

Animal Foods: mollusks; aquatic or marine worms; aquatic crustaceans; cnidarians; zooplankton

Plant Foods: algae; phytoplankton

Primary Diet: omnivore

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.

Biogeographic Regions: indian ocean (Native ); pacific ocean (Native )

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).

Range depth: 1 to 35 m.

Habitat Regions: tropical ; saltwater or marine

Aquatic Biomes: reef ; coastal

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)

Mating System: monogamous

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).

Breeding interval: Threadfin butterflyfish breed frequently. Factors influencing breeding frequency are not known.

Breeding season: Threadfin butterflyfish may breed throughout the year.

Average gestation period: 30 days.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous

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.

Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female)

Description: There is a pattern of `chevron' markings on the sides and a prominent black spot at the posterior edge of the soft portion of the dorsal fin. Adults of this species have a prominent black vertical band running across the eye, and a filament trailing posteriorly from the upper soft portion of the dorsal fin. Juveniles with a black bar over the head that hides the eye and an eye-sized black spot on the soft dorsal fin (Ref. 48636). Snout length 2.2-2.8 in HL. Body depth 1.6-1.8 in SL (Ref. 90102).

Hurleytrematoides Infestation 7. Parasitic infestations (protozoa, worms, etc.)

Uronema infection. Parasitic infestations (protozoa, worms, etc.)

Distinct pairing (Ref. 205). Monogamous mating is observed as both obligate and social (Ref. 52884).

Dorsal spines (total): 12 - 13; Dorsal soft rays (total): 22 - 25; Analspines: 3; Analsoft rays: 19 - 21

Occur inshore (Ref. 75154). Also found in groups or in pairs (Ref. 4859).

May be seen in a variety of habitats ranging from rich coral reefs (Ref. 58652) to weedy and rubble covered areas (Ref. 1602). Benthopelagic (Ref. 58302). Maybe found singly, in pairs, and in aggregations that roam over large distances in search of food. Feed mainly by tearing pieces from polychaetes, sea anemones, coral polyps, and algae (Ref. 1602). Oviparous (Ref. 205). Form pairs during breeding (Ref. 205).

fisheries: minor commercial; aquarium: commercial; price category: unknown; price reliability:

分布於印度-太平洋區，西起紅海、東非洲，東至夏威夷、馬貴斯群島(Marquesan Is.)及杜夕島(Ducie I.)，北至日本南部，南至羅得豪島(Lord Howe I.)及拉帕(Rapa I.)島。台灣各地岩礁及珊湖礁海域皆可見其蹤跡。

一般以潛水方式捕捉。為觀賞魚類，無食用經濟價值。

體高而呈橢圓形；頭部上方輪廓平直，鼻區處稍內凹。吻尖，但不延長為管狀。前鼻孔具鼻瓣。前鰓蓋緣具細鋸齒；鰓蓋膜與峽部相連。兩頜齒細尖密列，上頜齒7列，下頜齒9-11列。體被大型鱗片，菱形，呈斜上排列；側線向上陡昇至背鰭第IX棘下方而下降至背鰭基底末緣下方。背鰭單一，硬棘XII-XIII，軟條24，成魚之軟條部末端延長如絲狀；臀鰭硬棘III，軟條19-20。體前部銀白至灰黃色，後部黃色；體側前上方具5長條及3短條之向後斜上暗帶，後下方則具8-9條向前方斜上之暗帶，二者彼此呈直角交會；眼帶於眼上方窄於眼徑，眼下方則寬於眼徑；背鰭和臀鰭具黑緣；尾鰭後端前具黑緣之黃色橫帶；幼魚及成魚於背鰭軟條部均具眼斑。

棲息於碎石區、藻叢、岩礁或珊瑚礁區，單獨、成對或小群游動。主要以珊瑚蟲、多毛類、底棲甲殼類、腹足類及藻類等為食。

The threadfin butterflyfish (Chaetodon auriga) is a species of marine ray-finned fish belonging to the family Chaetodontidae. It has a wide Indo-Pacific distribution.

This species may be seen in a variety of habitats ranging from rich coral reefs to weed and rubble covered areas. It is found singly, in pairs, and in aggregations that roam over large distances in search of food. Feeds mainly by tearing pieces from polychaetes, sea anemones, coral polyps, and algae (Ref. 1602).