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Asian Bonytongue
Asian Bonytongue
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Asian Bonytongue  FISH

Scientific Name:
Scleropages formosus

Other Names and/or Listed subspecies:
Dragon Fish, Asian Arowana, Osteoglossum formosum, Kelesa, Golden Arowana, Golden Dragon Fish, Kelesa

Group: Fishes

Status/Date Listed as Endangered:
EN-US FWS: June 14, 1976

EN-IUCN: 2011

Area(s) Where Listed As Endangered:
Cambodia, Myanmar, Singapore, Thailand, Vietnam

Also called the Asian arowana, the Asian bonytongue is a freshwater fish found in the rivers of Malaysia, Indonesia, Thailand, and Myanmar. It is also called the dragon fish and is considered a lucky fish by natives because of its resemblance to the Chinese mythical dragon. Bonytongues get their name from the toothed bone (tongue) on the floor of the mouth that is equipped with teeth that bite against the upper teeth at the roof of the mouth. Adults have a stocky build and long bodies, growing up to 35 inches in length, and large, elongate pectoral, dorsal, and anal fins. It comes in many different colors, green being the most common. Others are silver, red, golden, and even blue in color. The mouth is wide and faces downward, opening like a drawbridge, and it is filled with many small teeth. The lower jaw has two barbells at the tip. The scales are large, and in some varieties they are metallic in color.

This species can only thrive in fresh water and is found in still streams and creeks. They are also bred on fishing farms and are popular as aquarium fish, requiring an enormous tank with at least 55 gallons of water. They are excellent jumpers and require a tight fitting cover if kept in aquariums. They are territorial and carnivorous, feeding on other fish, frogs, shrimps, worms, and insects. Asian bonytongues are "mouthbrooders;" The male fertilizes the eggs and he then cares for them by holding them in his mouth until they hatch and are able to swim freely. For this reason, the mouths of males are larger than females making it easy to determine the gender of individuals.

The main threat to the species is loss of habitat due to human disturbance. Also, some are captured illegally for the pet trade. This species is protected by law in its entire range, and only captive-bred Asian bonytongues can be sold or traded legally.

Asian Bonytongue Facts Last Updated: March 26, 2007

To Cite This Page:
Glenn, C. R. 2006. "Earth's Endangered Creatures - Asian Bonytongue Facts" (Online).
Accessed 3/27/2017 at


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