The silver arowana (''Osteoglossum bicirrhosum'') is a South American

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

bony fish Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a Biodiversity, diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondricht ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Osteoglossidae 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 f ...

. Silver arowanas are sometimes kept in

aquarium An aquarium (: 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. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

s, but they are predatory and require a very large tank. The generic name ''Osteoglossum'' means "bone-tongued" and the specific name ''bicirrhosum'' means "two barbels" (from the

Greek language Greek (, ; , ) is an Indo-European languages, Indo-European language, constituting an independent Hellenic languages, Hellenic branch within the Indo-European language family. It is native to Greece, Cyprus, Italy (in Calabria and Salento), south ...

Range and habitat

This South American species is native to the

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

, Essequibo and

Oyapock The Oyapock or Oiapoque ( ; ; ) is a long river in South America that forms most of the border between the French overseas department of French Guiana and the Brazilian state of Amapá. Course The Oyapock runs through the Guianan moist for ...

basins. It is absent from the Rio Negro basin, except the

Branco River The Branco River (; Engl: ''White River'') is the principal affluent of the Rio Negro from the north. Basin The river drains the Guayanan Highlands moist forests ecoregion. It is enriched by many streams from the Tepui highlands which separat ...

, which is inhabited by both silver and

black arowana The black arowana (''Osteoglossum ferreirai'') is a South American freshwater bony fish of the family Osteoglossidae. Black arowanas are sometimes kept in aquariums, but they are predatory and require a very large tank. It is generally common, bu ...

s. The silver arowana occurs in both black- and

whitewater Whitewater forms in the context of rapids, in particular, when a river's Stream gradient, gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that foam, froths, making t ...

habitats, including

flooded forest Freshwater swamp forests, or flooded forests, are forests which are inundated with freshwater, either permanently or seasonally. They normally occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are foun ...

Description

This fish has relatively large scales, a long body, and a tapered tail, with the dorsal and anal fins extending all the way to the small caudal fin, with which they are nearly fused. Its maximum total length is typically considered to be , but there are reports of individuals up to . Unlike the

, the silver arowana has the same coloring throughout its lifespan. Adults of the two species are very similar, but can be separated by

meristics Meristics is an area of zoology and botany which relates to counting quantitative features of animals and plants, such as the number of fins or scales in fish. A meristic (countable trait) can be used to describe a particular species, or used to i ...

Arowana 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 ...

s are sometimes called 'dragon fish' by aquarists because their shiny, armor-like scales and double barbels are reminiscent of descriptions of

dragon A dragon is a Magic (supernatural), magical legendary creature that appears in the folklore of multiple cultures worldwide. Beliefs about dragons vary considerably through regions, but European dragon, dragons in Western cultures since the Hi ...

s in East Asian folklore.

Behavior

The species is also called 'water monkey' because of its ability to jump out of the water and capture its

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 ...

. It usually swims near the water surface waiting for potential prey. Although specimens have been found with the remains of birds,

bat Bats are flying mammals of the order Chiroptera (). With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out ...

s, mice, and snakes in their stomachs, its main diet consists of snails, crustaceans (such as

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

s), insects (such as beetles), spiders, smaller fish, and other animals that float on the water surface, for which purpose its

drawbridge A drawbridge or draw-bridge is a type of moveable bridge typically at the entrance to a castle or tower surrounded by a moat. In some forms of English, including American English, the word ''drawbridge'' commonly refers to all types of moveable b ...

-like mouth is adapted.

Conservation status

The silver arowana is not currently listed on any

CITES CITES (shorter acronym for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of inte ...

appendix and is listed as

Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

on 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 an inventory of the global conservation status and extinction risk of biological ...

. It is one of the most popular ornamental fish from South America, however, and therefore its

conservation status The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation ...

merits attention. Other threats include

drought A drought is a period of drier-than-normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, ...

s and

deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...

siltation Siltation is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary o ...

and drainage of land for human use. As reported by '' Environment News Service'' in August 2005, shared use of the silver arowana population was a cause for a dispute between

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

ian and

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

n authorities. Juvenile silver arowanas are caught in Colombia for sale as aquarium fish, while the people of

ian Amazonia catch adult fish for food. A sharp drop in the number of arowanas had caused Brazilian authorities to prohibit fishing of them between September 1 and November 15; the Colombians would prohibit capturing them between November 1 and March 15. The silver arowana is often kept as a pet by experienced aquarists, being considered an accessible substitute for the

Asian arowana The Asian arowana (''Scleropages formosus'') comprises several phenotypic varieties of freshwater fish distributed geographically across Southeast Asia. While most consider the different varieties to belong to a single species, work by Pouyaud ' ...

, which is listed on CITES Appendix I and is therefore difficult and expensive to obtain legally.

References

External links