The African arowana or Nile arowana (''Heterotis niloticus'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

bonytongue Osteoglossidae is a family of large-sized freshwater fish, which includes the arowanas. They are commonly known as bonytongues. The family has been regarded as containing two extant subfamilies Arapaiminae and Osteoglossinae, with a total of fiv ...

. Despite being called an "arowana", the African arowana is more closely related to arapaimas, the only other members in the subfamily

Arapaiminae Arapaimidae is a Family (biology), family of freshwater Actinopterygii, ray-finned fish belonging to the order Osteoglossiformes. It includes the South American arapaimas of the Amazon Basin, Amazon and Essequibo River, Essequibo basins and the A ...

, than the South American, Asian, and Australian arowanas in the subfamily

Osteoglossinae Arowanas are freshwater bony fish of the subfamily Osteoglossinae, also known as bony tongues (the latter name is now often reserved for Arapaiminae). In this family of fish, the head is bony and the elongated body is covered by large, heavy sca ...

(Arapaiminae is sometimes considered to be a separate family from Osteoglossidae). Compared to these, the African arowana has a more terminal mouth and is the only one that feeds extensively on plankton.

Description

The African arowana is a long-bodied fish with large scales, long dorsal and anal fins set far back on the body, and a rounded caudal fin. Its height is 3.5 to 5.0 times

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

. It has been reported to reach up to long and weigh up to . This fish is gray, brown, or bronze in color. Coloration is uniform in adults, but juveniles often have dark longitudinal bands. African arowanas have air-breathing organs on its

branchiae A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

, enabling them to survive in oxygen-depleted water. A suprabranchial organ allows it to concentrate small planktonic food particles and also has a sensory function.

Range

This species is widespread throughout Africa, where it is native to all the watersheds in Sahelo-Sudanese region,

Senegal Senegal, officially the Republic of Senegal, is the westernmost country in West Africa, situated on the Atlantic Ocean coastline. It borders Mauritania to Mauritania–Senegal border, the north, Mali to Mali–Senegal border, the east, Guinea t ...

, and

Gambia The Gambia, officially the Republic of The Gambia, is a country in West Africa. Geographically, The Gambia is the List of African countries by area, smallest country in continental Africa; it is surrounded by Senegal on all sides except for ...

, as well as parts of eastern Africa. This range includes the basins of the Corubal, Volta, Ouémé,

Niger Niger, officially the Republic of the Niger, is a landlocked country in West Africa. It is a unitary state Geography of Niger#Political geography, bordered by Libya to the Libya–Niger border, north-east, Chad to the Chad–Niger border, east ...

Bénoué Bénoué is a Departments of Cameroon, department of North Province (Cameroon), North Province in Cameroon. The department covers an area of 13,614 km and as of 2005 had a total population of 1,781,955. The capital of the department lies at ...

, and

Nile The Nile (also known as the Nile River or River Nile) is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa. It has historically been considered the List of river sy ...

Rivers, as well as those of

Lake Chad Lake Chad (, Kanuri language, Kanuri: ''Sádǝ'', ) is an endorheic freshwater lake located at the junction of four countries: Nigeria, Niger, Chad, and Cameroon, in western and central Africa respectively, with a catchment area in excess of . ...

and

Lake Turkana Lake Turkana () is a saline lake in the Kenyan Rift Valley, in northern Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake. By volume it is the world ...

. It has been successfully introduced to

Côte d'Ivoire Ivory Coast, also known as Côte d'Ivoire and officially the Republic of Côte d'Ivoire, is a country on the southern coast of West Africa. Its capital city of Yamoussoukro is located in the centre of the country, while its largest city and ...

, the Cross River in

Nigeria Nigeria, officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf of Guinea in the Atlantic Ocean to the south. It covers an area of . With Demographics of Nigeria, ...

, the Sanaga and

Nyong River The Nyong (formerly ) is a river in Cameroon. The river flows approximately to empty into the Gulf of Guinea. Course The Nyong originates east of the town of Abong-Mbang, where the northern rain forest feeds it. The river's length is almost ...

s in

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

, and the

Ogooué River The Ogooué (or Ogowe), also known as the Nazareth River, some long, is the principal river of Gabon in west-central Africa and the fourth largest river in Africa by volume of discharge, trailing only the Congo, Kasai and Niger. Its watershed ...

Gabon Gabon ( ; ), officially the Gabonese Republic (), is a country on the Atlantic coast of Central Africa, on the equator, bordered by Equatorial Guinea to the northwest, Cameroon to the north, the Republic of the Congo to the east and south, and ...

, as well as the lower and middle

Congo River The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world list of rivers by discharge, by discharge volume, following the Amazon Ri ...

basin, including Ubangui and Kasaï Rivers. It has also been introduced in

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

. In some cases, introduction is reported to have had a negative impact on the local ecology.

Human use

African bonytongue total production thousand tonnes 1950-2022

African arowana is used locally as a food fish and has been collected in the past for the

aquarium trade Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. It is a practice that encompasses the art of maintaining one's own aquatic ecosystem, featuring a lot of variety with various ...

. It is not aggressive like its relatives. It is aquacultured in its native range, being a very successful culture due to its tolerance for crowding and ease of feeding.

References

External links

* {{Taxonbar, from1=Q387247, from2=Q14027417 Osteoglossidae Fish described in 1829 Taxa named by Georges Cuvier Fish of Lake Turkana Freshwater fish of West Africa