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. Although the term specifically excludes seawater and brackish water, it does incl ...

bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartil ...

of the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Osteoglossidae. Silver arowanas are sometimes kept in

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 ...

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 ( el, label= Modern Greek, Ελληνικά, Elliniká, ; grc, Ἑλληνική, Hellēnikḗ) is an independent branch of the Indo-European family of languages, native to Greece, Cyprus, southern Italy ( Calabria and Salento), souther ...

Range and habitat

This South American species is native to the

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

Essequibo Essequibo is the largest traditional region of Guyana but not an administrative region of Guyana today. It may also refer to: * Essequibo River, the largest river in Guyana * Essequibo (colony), a former Dutch colony in what is now Guyana; * Esseq ...

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 fores ...

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

Branco River The Branco River ( pt, Rio Branco; 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 is inhabited by both silver and black arowanas. The silver arowana occurs in both black- and

whitewater Whitewater forms in a rapid context, in particular, when a river's gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that froths, making the water appear opaque and ...

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 ...

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 black arowana, 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 ichthyology and herpetology which relates to counting quantitative features of fish and reptiles, such as the number of fins or scales. A meristic (countable trait) can be used to describe a particular species of fish, or us ...

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 sc ...

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 reptilian legendary creature that appears in the folklore of many cultures worldwide. Beliefs about dragons vary considerably through regions, but dragons in western cultures since the High Middle Ages have often been depicted a ...

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 where 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 kill ...

. It usually swims near the water surface waiting for potential prey. Although specimens have been found with the remains of birds, bats, mice, and snakes in their stomachs, its main diet consists of snails, crustaceans (such as

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all th ...

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

-like mouth is exclusively adapted for feeding on.

Conservation status

The silver arowana is currently not listed on any

CITES CITES (shorter name 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 intern ...

appendix nor on the 2004

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 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. As reported by ''

Environment News Service The Environment News Service (ENS), referred to as ENS, is an environmental news agency which provides original late-breaking news reports. First published on January 1, 1990, ENS is based in the United States. ENS is privately owned and operated ...

'' in August 2005, shared use of the silver arowana population was a cause for a dispute between

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

ian and

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the ...

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.Brazil, Colombia at Odds Over Silver Amazon Fish
A meeting between the representatives of the Amazon Basin countries in August 2005 was meant to discuss the dispute. 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 Pouyau ...

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

References