Animal Diversity Web

Ge­o­graphic Range

Am­phiprion ocel­laris (Cu­vier 1830), the false clown­fish, is a trop­i­cal ma­rine fish found in parts of Asia and Aus­tralia. Its range in­cludes North­west Aus­tralia, South­east Asia, and as far north as the Ryukyu Is­lands of Japan (Allen 1997). (Allen, 1997)

• Biogeographic Regions
• oriental
  • native
• australian
  • native
• pacific ocean
  • native

Habi­tat

Am­phiprion ocel­laris in­hab­its coral reefs (Allen 1997) and shel­tered la­goons up to a depth of 15 me­ters (Myers 1999). More specif­i­cally, it is mainly found in or near the anemones Het­er­ac­tis mag­nifica, Sti­chodactyla gi­gan­tean, and Sti­chodactyla merten­sii (Myers 1999) as part of a sym­bi­otic re­la­tion­ship. (Allen, 1997; Myers, 1999)

• Habitat Regions
• tropical
• saltwater or marine

• Aquatic Biomes
• reef

• Range depth

  15 to 1 m

  49.21 to 3.28 ft

Phys­i­cal De­scrip­tion

False clown­fish are or­ange to red­dish-brown with three white bands on the head and body. The white bands are out­lined in black. Black A. ocel­laris, with white bands and black col­or­ing in­stead of or­ange, are found off the North­ern Ter­ri­tory of Aus­tralia (Allen 1997). Am­phiprion ocel­laris has a rounded cau­dal fin and may grow up to 110 mm in length (Nel­son et al. 1996). There are 11 dor­sal spines and 17 pec­toral rays that help to dis­tin­guish it from the closely re­lated Am­phiprion per­cula. Fe­males are larger than males in this species. (Allen, 1997; Nel­son, et al., 1996)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger

• Range length

  110 (high) mm

  4.33 (high) in

• Average length

  80 mm

  3.15 in

De­vel­op­ment

Am­phiprion ocel­laris hatches and en­ters a short lar­val stage where it re­sides close to the sur­face in a plank­tonic stage. As they change from lar­vae to ju­ve­nile fish, usu­ally within a day, the fish moves from the sur­face to the bot­tom in search of a host anemone (Fautin and Allen 1992). (Fautin and Allen, 1992)

• Development - Life Cycle
• metamorphosis

Re­pro­duc­tion

In­for­ma­tion specif­i­cally for A. ocel­laris mat­ing habits is not avail­able, but gen­eral be­hav­ior be­lieved to be typ­i­cal of all anemone­fishes is doc­u­mented. They are ter­ri­to­r­ial to the spe­cific anemone they in­habit and are monog­a­mous (Thresher 1984). Prior to spawn­ing, nest prepa­ra­tion is done by the male, where sub­strate is cleared to make a nest on bare rock, but near enough to the anemone to still have pro­tec­tion from the over­hang­ing ten­ta­cles (Thresher 1984). Males will at­tract the fe­male by ex­tend­ing fins, bit­ing, and chas­ing (Fautin and Allen 1992). Dur­ing spawn­ing, the males are in­creas­ingly ag­gres­sive. (Fautin and Allen, 1992; Thresher, 1984; Fautin and Allen, 1992; Thresher, 1984)

• Mating System
• monogamous

Am­phiprion ocel­laris is part of a the sub­fam­ily Am­phipri­on­i­nae, or anemone­fishes. This group is char­ac­ter­ized by being protan­drous her­maph­ro­dites, mean­ing that all in­di­vid­u­als de­velop first into males and then pos­si­bly into fe­males later (Myers 1999). An adult male and fe­male and sev­eral ju­ve­niles may re­side to­gether in an anemone. If the fe­male were to be re­moved or die, the largest male would then be­come the fe­male, with the larger of the im­ma­ture fish trans­form­ing into a male. Fe­males con­trol males with ag­gres­sive dom­i­nance, thus con­trol­ling the cre­ation of other fe­males (Fricke and Fricke 1977). The largest male will in turn dom­i­nate the ju­ve­niles and pre­vents other males from spawn­ing (Fricke and Fricke 1977).

Am­phiprion ocel­laris is able to breed nearly year round be­cause it in­hab­its trop­i­cal wa­ters (Thresher 1984) but may be some­what lim­ited in the north­ern reaches of its dis­tri­b­u­tion dur­ing win­ter months. Spawn­ing is con­cen­trated around the full moon and usu­ally oc­curs in the morn­ing. Pos­si­ble rea­sons for this in­clude: stronger water cur­rents for lar­val dis­tri­b­u­tion, greater food sup­plies due to in­ver­te­brate spawn­ing at the same time, and over­all in­creased vis­i­bil­ity (Thresher 1984).

When spawn­ing is about to occur, the male will chase the fe­male to the nest, but the fe­male ac­tu­ally be­gins the process. The fe­male makes sev­eral passes over the nest and even­tu­ally lays or­ange eggs over the pe­riod of 1-2 hours be­fore leav­ing the nest (Thresher 1984). Eggs are ap­prox­i­mately 3-4 mm in length and range in num­ber from 100-1000 de­pend­ing on the age of the fish (Fautin and Allen 1992). The male then con­tin­ues the process as he passes over the eggs, fer­til­iz­ing them. Eggs are at­tached to the sub­strate with a fine thread. In­cu­ba­tion is af­fected by water tem­per­a­ture, the cooler the water, the longer in­cu­ba­tion pe­riod, but in gen­eral it re­quires 6-8 days be­fore hatch­ing oc­curs (Thresher 1984). The plank­tonic lar­val stage lasts from 8-12 days and ends when the ju­ve­nile fish set­tle re­turns to the bot­tom and at­tempt to find an anemone to in­habit. (Fautin and Allen, 1992; Fricke and Fricke, 1977; Myers, 1999; Thresher, 1984)

• Key Reproductive Features
• iteroparous
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sequential hermaphrodite
  • protandrous
• sexual
• fertilization
  • external
• oviparous

• Breeding season

  Spawing occurs year-round in the tropics, but only in warmer months in warm-temperate areas. Spawning occurs near the full moon.

• Average time to hatching

  7 days

Prior to spawn­ing, males pre­pare a nest where the eggs will be de­posited. Males ac­count for the ma­jor­ity of the egg care, but fe­males are in­volved spo­rad­i­cally. Main du­ties in­clude fan­ning the eggs and eat­ing eggs that are in­fer­tile or dam­aged by fun­gus (Thresher 1984). Once the eggs hatch into the lar­val stage, they are in­de­pen­dent of the par­ents. (Thresher, 1984)

• Parental Investment
• pre-fertilization
  • protecting
    • male
• pre-hatching/birth
  • protecting
    • male

Lifes­pan/Longevity

Lifes­pan has not been stud­ied fully in the wild, but it is be­lieved that A. ocel­laris may live 6-10 years (Fautin and Allen 1992). Lar­val fish are ex­tremely sus­cep­ti­ble to pre­da­tion as they have no way of de­fend­ing them­selves and have high mor­tal­ity rates. Cap­tiv­ity trans­fer ex­per­i­ments have been per­formed to ad­dress the pos­si­bil­ity of re­stock­ing the fish in areas where they have been de­pleted; these find that sur­vival among trans­ferred fish is higher among smaller A. ocel­laris (Nel­son et al. 1996). (Fautin and Allen, 1992; Nel­son, et al., 1996)

• Typical lifespan
  Status: wild

  6 to 10 years

Be­hav­ior

Am­phiprion ocel­laris ex­ists in a sym­bi­otic re­la­tion­ship with sea anemones, specif­i­cally, Het­er­ac­tis mag­nifica, Sti­chodactyla gi­gan­tean, and Sti­chodactyla merten­sii (Myers 1999). These fish are de­pen­dent upon the anemone for shel­ter. In open wa­ters these fish are more sus­cep­ti­ble to preda­tors and are poor swim­mers. In ad­di­tion, anemones pro­vide pro­tec­tion for the nests (Fautin and Allen 1992). The anemones are ob­served to gen­er­ally do bet­ter with a host fish and may also ben­e­fit pos­si­bly from fish con­sump­tion of par­a­sites and in­creased water cir­cu­la­tion from fan­ning (Fautin and Allen 1992). Anemone­fishes are pro­tected from the sting of the anemone by their mucus (Fautin and Allen 1992). There is a pe­riod of ac­clima­ti­za­tion that must occur be­fore the fish is im­mune to the anemone sting. This in­volves a process in which the fish swims around the anemone rub­bing its belly and ven­tral fins on the ends of the ten­ta­cles (MarineBio 1998).

As the ju­ve­niles search for an anemone, their sur­vival is con­tin­gent upon find­ing an anemone to re­side in, but this process is com­pli­cated by the dy­nam­ics within the anemone. Be­cause of the hi­er­ar­chi­cal dy­nam­ics within the anemone, the new ju­ve­nile fish en­ters the sys­tem at the bot­tom and is ex­posed to the worst ag­gres­sion and may be dri­ven away (Thresher 1984). A. ocel­laris are able to find one of the three species of sea anemones by ol­fac­tory clues, due to im­print­ing that oc­curred while in the nest (Arved­lund and Nielsen 1996). (Arved­lund and Nielsen, 1996; Fautin and Allen, 1992; MarineBio, 1998; Myers, 1999; Thresher, 1984)

• Key Behaviors
• natatorial
• diurnal
• motile
• sedentary
• social
• dominance hierarchies

Com­mu­ni­ca­tion and Per­cep­tion

Com­mu­ni­ca­tion dur­ing mat­ing oc­curs through the male bit­ing, chas­ing, and ex­tend­ing his fins to­wards the fe­male (Thresher 1984). The hi­er­ar­chi­cal sys­tem is com­mu­ni­cated through ag­gres­sion by the larger mem­bers re­sid­ing in the anemone at the smaller in­di­vid­u­als. Ampiprion ocel­laris is able to find host anemones by ol­fac­tory im­print­ing that oc­curs while in the nest (Ar­vend­lund and Nielsen 1996). (Arved­lund and Nielsen, 1996; Thresher, 1984)

• Communication Channels
• visual
• tactile

• Perception Channels
• visual
• tactile
• chemical

Food Habits

Plank­tonic food such as zoo­plank­ton, cope­pods, and algae are the pri­mary source of food for A. ocel­laris (Myers 1999). They are clas­si­fied as gen­er­al­ized om­ni­vores as they feed on equal amounts of algae and an­i­mals (Sano et al. 1984). They are also re­ported to con­sume par­a­sites from their host anemones (Thresher 1984). Feed­ing is also dom­i­nated by the hi­er­ar­chi­cal struc­ture of the group dy­nam­ics in the anemone. Be­cause the smaller fish re­ceive the most ag­gres­sion from the oth­ers, they have re­duced en­ergy for for­ag­ing great dis­tances from the anemone and tend to stay close. Ad­di­tion­ally, it is un­safe for the smaller fish to stray far­ther from the safety of the anemone (Fautin and Allen 1992). The large, dom­i­nant fish will for­age at greater dis­tances, but gen­er­ally no far­ther than sev­eral me­ters from the anemone. (Fautin and Allen, 1992; Myers, 1999; Sano, et al., 1984; Thresher, 1984)

• Primary Diet
• planktivore

• Animal Foods
• aquatic crustaceans
• zooplankton

• Plant Foods
• algae

Pre­da­tion

Pre­da­tion on anemone­fishes is greatly re­duced due to the re­la­tion­ship with the host anemone, whose sting de­ters po­ten­tial preda­tors. The eggs are more sus­cep­ti­ble to pre­da­tion, mainly by other dam­selfishes (Po­ma­cen­tri­dae) not in­clud­ing other anemone­fishes, and wrasses (Labri­dae) (Arved­lund et al. 2000). Egg pre­da­tion sus­cep­ti­bil­ity in­creases at night as the male is not guard­ing them and they may fall vic­tim to brit­tle stars (Ophiotrichi­dae) (Arved­lund et al. 2000). (Arved­lund, et al., 2000)

• Known Predators

  • wrasses (Labridae)
  • damselfishes (Pomacentridae)

Ecosys­tem Roles

As men­tioned pre­vi­ously (Be­hav­ior), A. ocel­laris is part of a sym­bi­otic re­la­tion­ship be­tween three species of sea anemones, Het­er­ac­tis mag­nifica, Sti­chodactyla gi­gan­tean, and Sti­chodactyla merten­sii (Myers 1999). In this re­la­tion­ship, the fish re­ceives pro­tec­tion from the anemone in the form of daily shel­ter and for its nest. The anemone re­ceives pro­tec­tion too, as it has been doc­u­mented that in the ab­sence of a guest fish, the anemones may be at­tacked by but­ter­fly fish or even tur­tles (MarineBio 1998). Ad­di­tion­ally, in the pres­ence of the fish, bulbs are found on the end of ten­ta­cles that are be­lieved to in­crease sur­face area avail­able to solar en­ergy (Fautin and Allen 1992). The bulbs are not pre­sent in the ab­sence of the fish. (Fautin and Allen, 1992; MarineBio, 1998; Myers, 1999)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Am­phiprion ocel­laris are part of the trop­i­cal fish aquar­ium trade and cer­tain rare col­ors of the species are specif­i­cally sought (Sadovy and Vin­cent 2002). They are eas­ily bred in cap­tiv­ity and may be used in re­search (Thresher 1984). (Sadovy and Vin­cent, 2002; Thresher, 1984)

• Positive Impacts
• pet trade
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

None known

Con­ser­va­tion Sta­tus

The high de­mand for the A. ocel­laris in the aquar­ium trade has re­duced the pop­u­la­tion size in some lo­ca­tions, leav­ing the local pop­u­la­tions open to over-ex­ploita­tion and other threats (Nel­son et al. 1996). The species is not clas­si­fied as threat­ened or en­dan­gered (IUCN 2003); how­ever, as threats to coral reefs in­crease, A. ocel­laris may face habi­tat degra­da­tion and pos­si­bly be threat­ened in the fu­ture. Coral reefs face many is­sues in­clud­ing sed­i­men­ta­tion, eu­troph­i­ca­tion, ex­ploita­tion of re­sources, and pos­si­ble sea tem­per­a­ture in­creases due to global warm­ing (Bhat 2004). (Bhat, 2004; IUCN, 2003; Nel­son, et al., 1996)

• IUCN Red List

  Not Evaluated

• US Federal List

  No special status

• CITES

  No special status

Con­trib­u­tors

Matthew Wund (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Dani New­comb (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, William Fink (ed­i­tor, in­struc­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Allen, G. 1997. Ma­rine Fishes of Trop­i­cal Aus­tralia and South-East Asia. Perth: West­ern Aus­tralian Mu­seum.

Arved­lund, M., I. Bundgaard, L. Nielsen. 2000. Host im­print­ing in anemone­fishes (Pisces: Po­ma­cen­tri­dae): does it dic­tate spawn­ing site pref­er­ences?. En­vi­ron­men­tal Bi­ol­ogy of Fishes, 58: 203-213.

Arved­lund, M., L. Nielsen. 1996. Do the anemone­fish Am­phiprion ocel­laris (Pisces: Po­ma­cen­tri­dae) im­print them­selves to their host sea anemone Het­er­ac­tis mag­nifica (Atho­zoa: Ac­tinidae)?. Ethol­ogy, 102: 197-211.

Bhat, A. 2004. Coral reefs and their fauna: An un­der­wa­ter fan­ta­sy­land. Res­o­nance, Sep­tem­ber: 62-73.

Fautin, D., G. Allen. 1992. Field Guide to Anemone­fishes and their Host Sea Anemones. Perth: West­ern Aus­tralian Mu­seum.

Fricke, H., S. Fricke. 1977. Monogamy and sex change by ag­gres­sive dom­i­nance in coral reef fish. Na­ture, 266: 830-832.

IUCN, 2003. "2003 IUCN Red List of Threat­ened Species" (On-line). Ac­cessed Oc­to­ber 22, 2004 at www.​iucnredlist.​org.

MarineBio, 1998. "False Clown­fish" (On-line). Ac­cessed Oc­to­ber 21, 2004 at http://​www.​marinebio.​com/​species.​asp?​id=29.

Myers, R. 1999. Mi­cone­sian Reef Fish: A Field Guide for Divers and Aquar­ists. Bar­ri­gada: Ter­ri­tory of Guam: Coral Graph­ics.

Myr­berg, Jr., A., L. Fuiman. 2002. The Sen­sory World of Coral Reef Fishes. Pp. 146 in P Sale, ed. Coral Reef Fishes. San Diego, Cal­i­for­nia: Aca­d­e­mic Press.

Nel­son, J., P. Phang, L. Chou. 1996. Sur­vival and growth rates of the anemone­fish Am­phiprion ocel­laris: a trans­fer ex­per­i­ment. Jour­nal of Fish Bi­ol­ogy, 48: 1130-1138.

Sadovy, Y., A. Vin­cent. 2002. Eco­log­i­cal Issue and the Trade in Live Reef Fishes. Pp. 395 in P Sale, ed. Coral Reef Fishes. San Diego, Cal­i­for­nia: Aca­d­e­mic Press.

Sano, M., M. Shimizu, Y. Nose. 1984. Food habits of teleostean reef fishes in Ok­i­nawa Is­land, South­ern Japan. Japan: Uni­ver­sity of Tokyo Press.

Thresher, R. 1984. Re­pro­duc­tion in Reef Fishes. New Jer­sey: T.F.H. Pub­li­ca­tions, Inc..