The clown featherback (''Chitala ornata''), also known as the clown knifefish and spotted knifefish, is a

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

species of

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

fish with a long, knife-like body. This knifefish is native to freshwater habitats in Cambodia, China, Hong Kong, Laos, Macau, Thailand, and Vietnam, but it has also been introduced to regions outside its native range. It is one of the world's most

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

. It is often seen in

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. Nelu ...

and the aquarium trade, where it is frequently confused with ''

Chitala chitala ''Chitala chitala'' (Assamese: চিতল ''sitawl'', Bengali: চিতল, ''chitol'') is a knifefish from Bangladesh, India, Nepal, and Pakistan, found in the Brahmaputra, Indus, Ganges and Mahanadi River basins. It is sometimes known as ...

''; 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, China, Hong Kong, Laos, Macau, Thailand, and Vietnam, where it is found in the

Mekong The Mekong or Mekong River ( , ) is a transboundary river in East Asia and Southeast Asia. It is the world's twelfth-longest river and the third-longest in Asia with an estimated length of and a drainage area of , discharging of wat ...

Chao Phraya The Chao Phraya River 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. Etymology Written evidence of the river being referred to by the ...

, and Meklong River basins. It has also been introduced to regions outside its native range, including the Philippines, Indonesia, Myanmar, Singapore, Sri Lanka,

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

and

Palm Beach County Palm Beach County is a county in the southeastern part of Florida, located in the Miami metropolitan area. It is Florida's third-most populous county after Miami-Dade County and Broward County and the 24th-most populous in the United States, wi ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

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

Broward County Broward County ( ) is a County (United States), county in Florida, United States, located in the Miami metropolitan area. It is Florida's second-most populous county after Miami-Dade County, Florida, Miami-Dade County and the List of the most ...

, Florida.

Appearance

The clown knifefish is very distinct, with normally silvery 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 ''

''; 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 reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...

s and

leucistic Leucism () is a wide variety of conditions that result in 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 ''leu ...

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 Nasal is an adjective referring to the nose, part of human or animal anatomy. It may also be shorthand for the following uses in combination: * With reference to the human nose: ** Nasal administration, a method of pharmaceutical drug delivery * ...

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 main ...

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

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

and has no

ventral fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hind ...

Behavior

They are

and usually cruise during the

twilight Twilight is daylight illumination produced by diffuse sky radiation when the Sun is below the horizon as sunlight from the upper atmosphere is scattered in a way that illuminates both the Earth's lower atmosphere and also the Earth's surf ...

hours. They normally hunt live

prey Predation is a biological interaction in which 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 ki ...

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. The clown knifefish prefers water around neutral pH and temperatures ranging from . These fish usually are found in lakes, 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 caves, 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 may refer to: Technology * Feeder (livestock equipment) * Feeder (beekeeping), any of several devices used in apiculture to supplement or replace natural food sources * Feeder (casting), another name for a riser, a reservoir built into ...

, 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 (, , ) is the national cuisine of Thailand. Thai cooking places emphasis on lightly prepared dishes with aromatics and spicy heat. The Australian chef David Thompson, an expert on Thai food, observes that unlike many other cui ...

and other Southeast Asian countries. In Thailand, when deep-fried as ''pla krai thot krathiam'', it is served with a spicy dipping sauce on the side made by mashing up

coriander Coriander (), whose leaves are known as cilantro () in the U.S. and parts of Canada, and dhania in parts of South Asia and Africa, is an annual plant, annual herb (''Coriandrum sativum'') in the family Apiaceae. Most people perceive the ...

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, L ...

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

fish ball Fish balls are 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 potato star ...

References

External links

* 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 {{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