The clown featherback, clown knifefish, or spotted knifefish, ''Chitala ornata'', is a nocturnal

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

fish with a long, knife-like body. This knifefish is native to freshwater habitats in

Cambodia Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailan ...

, Laos,

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

, and

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...

, but it has also been introduced to regions outside its native range. It is one of the world's most invasive species. It is often seen in aquaculture and the aquarium trade, where it is frequently confused with '' Chitala chitala''; the latter species is very rare in the aquarium trade.Seriously Fish:
Chitala ornata.
' Retrieved 24 May 2014 The clown featherback reaches in length, outgrowing all but the largest aquaria, yet it is popular.

Distribution

This species is native to Cambodia, Laos, Thailand, and Vietnam, where found in the

Mekong The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annual ...

Chao Phraya The Chao Phraya ( or ; th, แม่น้ำเจ้าพระยา, , or ) is the major river in Thailand, with its low alluvial plain forming the centre of the country. It flows through Bangkok and then into the Gulf of Thailand. E ...

, and Meklong River basins. It has also been introduced to regions outside its native range, including the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...

, Sri Lanka,

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

and

Palm Beach County Palm Beach County is a county located in the southeastern part of Florida and lies directly north of Broward County and Miami-Dade County. The county had a population of 1,492,191 as of the 2020 census, making it the third-most populous county ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, United States. It has either spread to or was introduced to

Broward County Broward County ( , ) is a county in the southeastern part of Florida, located in the Miami metropolitan area. It is Florida's second-most populous county after Miami-Dade County and the 17th-most populous in the United States, with over 1.94 m ...

, Florida.

Appearance

The clown knifefish is very distinct, with normally

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

y gray with a long, knife-like body (laterally compressed) and a long anal fin that gives it its common name. Mature fish normally have five to 10 (or even more) black spots ringed with white that usually decrease in size as the fish grows. These ocellated spots and the lack of faint stripes on the back separate it from '' Chitala chitala''; a species with which it frequently has been confused.Roberts, T.R. (1992). ''Systematic revision of the old world freshwater fish family Notopteridae.'' Ichthyol. Explor. Freshwat. 2(4):361-383.

Albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and pink or blue eyes. Individuals with the condition are referred to as albino. Varied use and interpretation of the term ...

s and

leucistic Leucism () is a wide variety of conditions that result in the partial loss of pigmentation in an animal—causing white, pale, or patchy coloration of the skin, hair, feathers, scales, or cuticles, but not the eyes. It is occasionally spelled ...

specimens are seen with some frequency in the aquarium trade. Juveniles lack the spots, but are overall striped. Their long anal fins are used to make graceful forward and backward movements. The clown knifefish grows to a fairly large size, up to and in the wild. It has two nasal

tentacles In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainl ...

above its large, toothed mouth. In the center of the body is a flag-like

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

and has no

ventral fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two ...

Behavior

They are nocturnal and usually cruise during the

twilight Twilight is light produced by sunlight scattering in the upper atmosphere, when the Sun is below the horizon, which illuminates the lower atmosphere and the Earth's surface. The word twilight can also refer to the periods of time when this i ...

hours. They normally hunt live

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

and try any fish that fits into their mouths. Young clown knifefish usually school near water logs and plants for security, whereas more mature specimens usually become territorial and eventually become loners. These fish can also breathe air to survive in stagnant waters and little

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

. The clown knifefish prefers water around neutral pH and temperatures ranging from . These fish usually are found in

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

s, swamps, and river backwaters.

In the aquarium

Clown knifefish are sold as exotic fish in pet stores, but they grow much too large for the average home aquarium. These fish have periods of retreat, so aquaria that have

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s, plants, or other hiding places are preferred. They are jumpers, so the lid should be kept tightly closed. Dim lighting may help lessen jumping. For the first few days, clown knifefish are shy and prone to hiding. As they grow larger, they tend to be quite the opposite.

Feeding

Clown knifefish are hearty eaters, and will take live foods such as

feeder fish Feeder fish is the common name for certain types of small, inexpensive fish commonly fed as live food to other captive animals such as predatory fishes (e.g. aquarium sharks, farmed salmon and tuna) or carnivorous aquarium fish (e.g. oscars, ...

, ghost shrimp, and blackworms. With time, they can be adapted to foods such as beefheart and will sometimes learn to accept commercial food pellets. They are mostly nocturnal, thus prefer feeding when the lights are off.

As food

The clown featherback is commonly seen in the

cuisine of Thailand Thai cuisine ( th, อาหารไทย, , ) is the national cuisine of Thailand. Thai cooking places emphasis on lightly prepared dishes with strong aromatic components and a spicy edge. Australian chef David Thompson, an expert on Thai ...

and other Southeast Asian countries. In Thailand, when deep-fried as ''pla krai thot krathiam'' (ปลากรายทอดกระเทียม), it is served with a spicy dipping sauce on the side made by mashing up coriander roots, bird's eye chillies, and garlic, and mixing this with

fish sauce Fish sauce is a liquid condiment made from fish or krill that have been coated in salt and fermented for up to two years. It is used as a staple seasoning in East Asian cuisine and Southeast Asian cuisine, particularly Myanmar, Cambodia, Lao ...

, lime juice, and sugar. The clown featherback is also the main fish used in the production of

fish ball Fish balls are rounded meat balls made from fish paste which are then boiled or deep fried. Similar in composition to fishcake, fish balls are often made from fish mince or surimi, salt, and a culinary binder such as tapioca flour, corn, or p ...

References

* http://www.myfwc.com/WILDLIFEHABITATS/Nonnative_FW_ClownKnifefish.htm – accessed October 2006 * http://badmanstropicalfish.com/profiles/profile5.html - accessed October 2006 * http://www.aqualandpetsplus.com/Knife,%20Clown.htm

External links

* {{Taxonbar, from=Q311166 Chitala Fish of Cambodia Fish of Laos Fish of Thailand Fish of Vietnam Fish described in 1831 Taxa named by John Edward Gray