''Balantiocheilos'' is a small

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

cyprinid Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest ...

fish from

southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainland ...

. It includes two

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

Species

*'' Balantiocheilos ambusticauda'' H. H. Ng &

Kottelat Maurice Kottelat (born 16 July 1957 in Delémont, SwitzerlandCo ...

, 2007 (Burnt tail fish) *'' Balantiocheilos melanopterus'' ( Bleeker, 1851) (Tricolor sharkminnow)

Distribution

The range of ''B. ambusticauda'' is listed as including the

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

Mae Klong The Mae Klong (, , ), sometimes spelled Mae Khlong or Meklong, is a river in western Thailand. The river begins at the confluence of the Khwae Noi (Khwae Sai Yok) and the Khwae Yai River (Khwae Si Sawat) in Kanchanaburi, it passes Ratchaburi ...

drainages in

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 ...

; the original distribution of this species included the Chao Phraya River drainage from

Bangkok Bangkok, officially known in Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estimated populati ...

upriver to the lower Nan River. It has also been reported in the Mekong Basin in

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 ...

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 Thailand ...

and

Laos Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist s ...

from the

Tonlé Sap Tonlé Sap (; km, ទន្លេសាប, ; or commonly translated as 'Great Lake'; vi, Biển Hồ, Chữ Hán: 湖海/壺海) is a lake in the northwest of Cambodia. It belongs to the Mekong River system. It is the largest freshwater l ...

lake to the lower

Nam Ngum Nam Ngum ( Laotian: ນໍ້າງືມ ) is a 354 km long river in Laos. It is a major tributary of the Mekong River. Geography The Nam Ngum originates from the northern mountainous region of Xiangkhoang Province and flows south through ...

River, but confirmed records from this basin are lacking and this is not recognized as part of its range by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

. Previous records of ''B. melanopterus'' from the same rivers is due to confusion with ''B. ambusticauda''; ''B. melanopterus'' only occurs in the

Malay Peninsula The Malay Peninsula ( Malay: ''Semenanjung Tanah Melayu'') is a peninsula in Mainland Southeast Asia. The landmass runs approximately north–south, and at its terminus, it is the southernmost point of the Asian continental mainland. The ar ...

Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

, and

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and e ...

. Large numbers of ''B. melanopterus'' are exported for the

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

trade from Thailand, but these are all captive bred.

Description

Cyprinid Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest ...

fishes of the genus ''Balantiocheilos'' are easily distinguished from other members of the family by the presence of thick and fleshy lips, the lower lip bearing a large lobe that is deeply incised medially along its posterior edge and black along the distal margins of the dorsal, caudal, anal and pelvic fins. The posterior margin of the lower lip has often been described as forming a posteriorly opening pouch or pocket between the lip and the skin of the throat. ''B. ambusticauda'' can be differentiated from ''B. melanopterus'' by a shorter snout. Also, in ''B. ambusticauda'' the rictus (junction of the premaxilla and maxilla at the corner of the mouth) has posteriorly direct grooves that are curved instead of straight. Finally, ''B. ambusticauda'' has narrower black margins on the pelvic and anal fins (on the distal third or less instead of the distal half or more in ''B. melanopterus''). ''B. ambusticauda'' also has some golden color as opposed to the silvery ''B. melanopterus''. ''B. ambusticauda'' only reaches about TL as opposed to TL in ''B. melanopterus''.

Conservation

''B. melanopterus'' is listed as an

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

by the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biolo ...

. It has become rare or

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

in many river basins of its native range. In Danau Sentarum (Borneo), fishermen already reported in 1993 and 1995 that the populations have decreased dramatically after 1975, for no clear reason. Fishermen mentioned overfishing for the aquarium-fish trade or forest fires in 1975 and the resulting pollution as possible causes. The species is apparently extirpated in the Batang Hari basin (

) and it seems that all individuals of ''B. melanopterus'' exported from Indonesia and Thailand by the aquarium-fish trade are captive bred. ''B. ambusticauda'' is believed to have gone

even before it was scientifically described. Humphrey & BainHumphrey, S.R. & Bain, J.R. (1990) Endangered animals of Thailand. Sandhill Crane Press, Gainesville, 468 pp. speculated the decline was due to excessive capture for the aquarium fish trade, but this is unsubstantiated. Despite the lack of records in more than three decades, it is rated as critically endangered (rather than extinct) by the IUCN in the hope that a small undiscovered population remains.

References

{{Taxonbar, from=Q2717593 Fish of South Asia ru:Акулий-бала