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Clownfish

Clownfish

Overview


Clownfish or anemonefish are fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

es from the subfamily Amphiprioninae in the family Pomacentridae
Pomacentridae
Pomacentridae are a family of perciform fish, comprising the damselfishes and clownfishes. They are primarily marine, while a few species inhabit freshwater and brackish environments . They are noted for their hardy constitutions and territoriality...

. Twenty-eight species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 are recognized, one in the genus Premnas
Maroon Clownfish
The maroon clownfish, Premnas biaculeatus, is a species of clownfish that is found in the Indo-Pacific from western Indonesia to Taiwan and the Great Barrier Reef. They can grow up to be about 17 cm , and as they grow, they become more aggressive towards other clownfish. It is also known as the...

, while the remaining are in the genus Amphiprion. In the wild they all form symbiotic
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...

 mutualisms with sea anemone
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...

s. Depending on species, clownfish are overall yellow, orange, reddish or blackish, and many show white bars or patches.
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Encyclopedia


Clownfish or anemonefish are fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

es from the subfamily Amphiprioninae in the family Pomacentridae
Pomacentridae
Pomacentridae are a family of perciform fish, comprising the damselfishes and clownfishes. They are primarily marine, while a few species inhabit freshwater and brackish environments . They are noted for their hardy constitutions and territoriality...

. Twenty-eight species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 are recognized, one in the genus Premnas
Maroon Clownfish
The maroon clownfish, Premnas biaculeatus, is a species of clownfish that is found in the Indo-Pacific from western Indonesia to Taiwan and the Great Barrier Reef. They can grow up to be about 17 cm , and as they grow, they become more aggressive towards other clownfish. It is also known as the...

, while the remaining are in the genus Amphiprion. In the wild they all form symbiotic
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...

 mutualisms with sea anemone
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...

s. Depending on species, clownfish are overall yellow, orange, reddish or blackish, and many show white bars or patches. The largest can reach a length of 18 centimetres (7.1 in), while the smallest barely can reach 10 centimetres (3.9 in).

Ecology and habitat


Clownfish are native to warmer waters of the Indian
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

 and Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 oceans, including the Great Barrier Reef
Great Barrier Reef
The Great Barrier Reef is the world'slargest reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres over an area of approximately...

 and the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...

. While most species have restricted distributions, others are widespread. Clownfish live at the bottom of the sea in sheltered reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....

s or in shallow lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...

s. There are no clownfish in the Atlantic.

Diet


Clownfish feed on small invertebrates which otherwise potentially could harm the sea anemone, and the fecal
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...

 matter from the clownfish provides nutrients to the sea anemone. Clownfish are omnivorous
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...

: in the wild they eat live food such as algae, plankton, mollusks, and crustacea; in captivity they can survive on live food, fish flakes, and fish pellets. Algae accounts for around 20 to 25 percent of its diet in the wild (and should also account for its amount of algae diet in captivity as well). The diet of the clownfish also consists of copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...

s, mysids
Mysidacea
Mysida is a group of small, shrimp-like crustaceans, an order in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch, or marsupium, in females. Mysids are mostly found in marine waters throughout the world, but are also important in...

, isopods
Isopoda
Isopods are an order of peracarid crustaceans, including familiar animals such as woodlice and pill bugs. The name Isopoda derives from the Greek roots and...

, zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...

 and undigested food from their host anemones.

Symbiosis and mutualism


Clownfish and sea anemones have a symbiotic, mutualistic relationship; each providing a number of benefits to the other. The individual species are generally highly host
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...

 specific, and especially the genera Heteractis
Stichodactylidae
Stichodactylidae is a family sea anemones that contains the genera Stichodactyla and Heteractis. These tropical sea anemones host several varieties of clownfish.*Genus: Heteractis**Heteractis aurora...

and Stichodactyla
Stichodactylidae
Stichodactylidae is a family sea anemones that contains the genera Stichodactyla and Heteractis. These tropical sea anemones host several varieties of clownfish.*Genus: Heteractis**Heteractis aurora...

, and the species Entacmaea quadricolor
Bubble-tip anemone
The bubble-tip anemone , also known as the bubble tip anemone, bubble anemone or bulb anemone, is a species of sea anemone of Indo-Pacific origin. In the wild, this anemone is a natural host of several species of anemonefishes, including the Cinnamon , Tomato , Orange-fin The bubble-tip anemone...

are frequent clownfish partners. The sea anemone protects the clownfish from predators, as well as providing food through the scraps left from the anemone's meals. In return, the clownfish defends the anemone from its predators, and cleans it from parasites. The anemone also potentially picks up nutrients from the Clownfish's excrement, and functions as a safe nest site. It has been theorized that the clownfish use their bright colouring to lure small fish to the anemone, and that the activity of the clownfish results in greater water circulation around the sea anemone.

Clownfish and certain damselfish
Damselfish
Damselfish comprise the family Pomacentridae except those of the genera Amphiprion and Premnas. They can grow up to long. While most are marine, a few species inhabit the lower stretches of rivers in freshwater. Damselfish usually have bright colors. in tropical coral reefs, and many of those are...

 are the only species of fishes that can avoid the potent poison of a sea anemone. There are several theories about how they can survive the sea anemone poison:
  • The mucus coating of the fish may be based on sugar
    Sugar
    Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...

    s rather than protein
    Protein
    Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

    s. This would mean that anemones fail to recognize the fish as a potential food source and do not fire their nematocyst
    Cnidocyte
    A cnidocyte, cnidoblast, or nematocyte is a type of venomous cell unique to the phylum Cnidaria . The cnidocyte cell provides a means for them to catch prey and defend themselves from predators. Despite being morphologically simple, lacking a skeleton and usually being sessile, cnidarians prey on...

    s, or sting organelle
    Organelle
    In cell biology, an organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid bilayer....

    s.
  • The coevolution of certain species of clownfish with specific anemone host species and may have acquired an immunity to the nematocysts and toxins of their host anemone. Experimentation has shown that Amphiprion percula may develop resistance to the toxin from Heteractis magnifica
    Heteractis magnifica
    Heteractis magnifica, also known by the common names magnificent sea anemone or Ritteri anemone, is a species of sea anemone that lives in the Indo-Pacific area, and can grow up to 1 metre in diameter in the wild. It can be kept in aquaria but is considered one of the most challenging species...

    , but it is not totally protected, since it was shown experimentally to die when its skin, devoid of mucus, was exposed to the nematocysts of its host.

Behavior


In a group of clownfish, there is a strict dominance hierarchy
Dominance hierarchy
A dominance hierarchy is the organization of individuals in a group that occurs when competition for resources leads to aggression...

. The largest and most aggressive female is found at the top. Only two clownfish, a male and a female, in a group reproduce through external fertilization
External fertilization
External fertilization is a form of fertilization in which a sperm cell is united with an egg cell external to the bodies of the reproducing individuals. In contrast, internal fertilization takes place inside the female after insemination through copulation....

. Clownfish are sequential hermaphrodites, meaning that they develop into males first, and when they mature, they become females. If the female clownfish is removed from the group, such as by death, one of the largest and most dominant males will become a female. The remaining males will move up a rank in the hierarchy.

Clownfish lay eggs on any flat surface close to their host anemones. In the wild, clownfish spawn around the time of the full moon. Depending on the species, clownfish can lay hundreds or thousands of eggs. The male parent guards the eggs until they hatch about 6 to 10 days later, typically 2 hours after dusk.

In the aquarium


Clownfish were the first type of marine ornamental fish to be successfully bred in captivity on a large scale. It is one of a handful of marine ornamentals whose complete life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...

 has been closed in captivity. Members of some clownfish species, such as the maroon clownfish, become aggressive in captivity; others, like the false percula clownfish, can be kept successfully with other individuals of the same species.

Clownfish are now reared in captivity by a handful of marine ornamental farms in the USA. Clownfish were the first species of Saltwater fish to successfully be Tank-raised. Tank-raised fish are a better choice for aquarist, because wild-caught fish are more likely to die soon after purchasing them due to the stress of capture and shipping. Also, tank-bred fish are usually more disease resistant and in general are less affected by stress when introduced to the aquarium. Captive bred clownfishes may not have the same instinctual behavior to live in an anemone. They may have to be coaxed into finding the anemone by the home aquarist. Even then, there is no guarantee that the anemone will host the clownfish.

When a sea anemone is not available in an aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

, the clownfish may settle in some varieties of soft coral
Alcyonacea
The Alcyonacea, or the soft corals are an order of corals which do not produce calcium carbonate skeletons. Soft corals contain minute, spiny skeletal elements called sclerites. Aside from their scientific utility in species identification, sclerites give these corals some degree of support and...

s, or large polyp stony corals. If the fish settles in a coral, it could agitate the fish's skin, and, in some cases, may kill the coral. Once an anemone or coral has been adopted, the clownfish will defend it. As there is less pressure to forage for food in an aquarium, it is common for clownfish to remain within 2-4 inches of their host for an entire lifetime.

Taxonomy

  • Genus Amphiprion:
    • Amphiprion akallopisos
      Amphiprion akallopisos
      The skunk clownfish or nosestripe anemonefish, Amphiprion akallopisos, is an anemonefish that lives in association with sea anemones. A. akallopisos, like A. percula, is nearly always associated with Heteractis magnifica and Stichodactyla gigantea, and is found in the Indo-Pacific...

      – Skunk clownfish
    • Amphiprion akindynos
      Barrier Reef Anemonefish
      The Barrier Reef Anemonefish, Amphiprion akindynos, is an anemonefish of the family Pomacentridae. It is native to reefs and marine lagoons of the Western Pacific.-Description:...

      – Barrier Reef Anemonefish
    • Amphiprion allardi
      Allard's Clownfish
      Allard's clownfish, Amphiprion allardi, is named after Jack Allard by Herbert Axelrod after his visit to Allards Collecting Station in Kenya.It is commonly seen with the bubble tip anemone....

      – Twobar anemonefish
    • Amphiprion bicinctus
      Red Sea clownfish
      The Red Sea clownfish / anemonefish , meaning "both sawlike with two stripes" is a clownfish of the family Pomacentridae.-Description:...

      – Twoband anemonefish
    • Amphiprion chagosensis – Chagos anemonefish
    • Amphiprion chrysogaster – Mauritian anemonefish
    • Amphiprion chrysopterus
      Orange-fin Anemonefish
      The orange-fin anemonefish or orange-fin clownfish, Amphiprion chrysopterus, is a clownfish, found in the Western Pacific north of the Great Barrier Reef from the surface to 20 m. It can grow to 16 cm in length....

      – Orange-fin anemonefish
    • Amphiprion clarkii
      Clark's anemonefish
      Clark's anemonefish or the Yellowtail clownfish is a widely distributed clownfish. It is found in tropical waters, in lagoons and on outer reef slopes, from the Persian Gulf to Western Australia and throughout the Indian Ocean and Pacific Ocean as far as Melanesia and Micronesia, and as far north...

      – Yellowtail clownfish
    • Amphiprion ephippium
      Red saddleback anemonefish
      The red saddleback anemonefish, Amphiprion ephippium, also known as the saddle anemonefish, is a clownfish that lives in the Indo-Pacific area. They are very colorful fish blazing bright red with a black area near the Dorsal fin....

      – Saddle anemonefish
    • Amphiprion frenatus
      Tomato Clownfish
      The tomato clownfish, Amphiprion frenatus, is a clownfish that is found in the waters of the Western Pacific, from the Ryukyu Islands, Japan, to Malaysia and Indonesia. It is also known as the bridled clownfish, red clownfish, or tomato anemonefish.The adult fish is bright orange-red, with one...

      – Tomato clownfish
    • Amphiprion fuscocaudatus – Seychelles anemonefish
    • Amphiprion latezonatus – Wide-band Anemonefish
    • Amphiprion latifasciatus – Madagascar anemonefish
    • Amphiprion leucokranos – Whitebonnet anemonefish
    • Amphiprion mccullochi – Whitesnout anemonefish
    • Amphiprion melanopus
      Cinnamon Clownfish
      Cinnamon clownfish or fire clownfish is a widely distributed clownfish. It is found in Indonesia, Melanesia, Micronesia, southeastern Polynesia, and the Great Barrier Reef....

      – Fire clownfish
    • Amphiprion nigripes
      Amphiprion nigripes
      Amphiprion nigripes, also known as the Blackfinned anemonefish or Maldives anemonefish, is a clownfish of the genus Amphiprion. -Description:...

      – Maldive anemonefish
    • Amphiprion ocellaris
      Ocellaris Clownfish
      The Ocellaris Clownfish, Clownfish or False Percula Clownfish is a popular aquarium fish. It is very closely related to A. percula, the Orange Clownfish or "True Percula Clownfish", and often lives in association with the sea anemone Heteractis magnifica, using them for shelter and protection...

      – Clown anemonefish
    • Amphiprion omanensis – Oman anemonefish
    • Amphiprion percula – Orange clownfish
    • Amphiprion perideraion
      Pink skunk clownfish
      The pink skunk clownfish or pink anemonefish, Amphiprion perideraion, is a skunk clownfish found in the west Pacific Ocean. It is known to be one of the smaller clownfish. They can be found off the Cocos and Christmas Islands in the eastern Indian Ocean, and the Indo-Australian...

      – Pink skunk clownfish
    • Amphiprion polymnus
      Saddleback clownfish
      The saddleback clownfish, Amphiprion polymnus, also known as the saddleback anemonefish is a member of the family Pomacentridae.- Habitat :...

      – Saddleback clownfish
    • Amphiprion rubacinctus
      Australian Clownfish
      The Australian clownfish , also known as the Red Anemonefish, is a type of clown fish found in tropical seas of Australia...

      – Red Anemonefish
    • Amphiprion sandaracinos
      Orange Skunk Clownfish
      The orange skunk clownfish, Amphiprion sandaracinos, also known as the skunk-striped anemonefish is a type of clownfish that is very bright orange, with a white stripe on the dorsal ridge from the mouth, between the eyes and ending after the dorsal fin...

      – Yellow clownfish
    • Amphiprion sebae
      Sebae Clownfish
      The sebae clownfish, Amphiprion sebae, is a very rare clownfish found in the northern Indian Ocean, which includes India, Sri Lanka, and the Maldive Islands. They can be very aggressive as they get older, like all damselfish. They can grow to 12 cm .Clownfish are the most popular species to...

      – Sebae anemonefish
    • Amphiprion thiellei – Thielle's anemonefish
    • Amphiprion tricinctus
      Three-band anemonefish
      The three-band anemonefish, Amphiprion tricinctus, is a type of clownfish found near the Marshall Islands and in the western part of the Pacific Ocean. They can be found in lagoons around 3 to 40 m deep...

      – Three-band anemonefish
  • Genus Premnas:
    • Premnas biaculeatus
      Maroon Clownfish
      The maroon clownfish, Premnas biaculeatus, is a species of clownfish that is found in the Indo-Pacific from western Indonesia to Taiwan and the Great Barrier Reef. They can grow up to be about 17 cm , and as they grow, they become more aggressive towards other clownfish. It is also known as the...

      – Maroon clownfish

In popular culture


In the 2003 animated film Finding Nemo
Finding Nemo
Finding Nemo is a 2003 American comi-drama animated film written by Andrew Stanton, directed by Andrew Stanton and Lee Unkrich and produced by Pixar. It tells the story of the overly protective clownfish Marlin who, along with a regal tang called Dory , searches for his abducted son Nemo...

, there were two clownfishes who both played a very prominent role in the film. The film told the story of a young clownfish called Nemo, who goes missing and his father Marlin, also a clownfish, goes on an adventure to get him back.

External links