Silver arowana
Encyclopedia
The silver arowana, Osteoglossum bicirrhosum, sometimes spelled arawana, is a freshwater
bony fish of the family
Osteoglossidae, commonly kept in aquaria
. The term "Osteoglossum" means "bone-tongued" and "bicirrhosum" means "two barbels" (from the Greek language
).
basin and in the Rupununi and Oyapock River
s in South America
as well as in still waters in Guyana
.
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. It can grow to a maximum size of 90 centimetres (35.4 in). Unlike the Black arowana
, Silver arowanas have the same coloring throughout their lifespan.
The species is also called monkey fish because of its ability to jump out of the water and capture its prey. It usually swims near the water surface waiting for potential prey. Although specimens have been found with the remains of birds, bats, and snakes in their stomachs, its main diet consists of crustaceans, insects, smaller fishes and other animals that float on the water surface, for which its draw-bridge-like mouth is exclusively adapted for feeding.
Arowana
are sometimes called Dragon Fish by aquarists because their shiny armor-like scales and double barbels are reminiscent of descriptions of dragon
s in Asian folklore.
. It is one of the most popular ornamental fish from South America, however, and therefore its conservation status
merits attention.
As reported by Environment News Service
in August 2005, shared use of the Silver Arowana population was a cause for a dispute between Brazil
ian and Colombia
n authorities. Juvenile Silver Arowanas are caught in Colombia for sale as aquarium fish, while the people of Brazil
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, on their part, would prohibit capturing them between November 1 and March 15.
The Silver Arowana is often kept as a pet by experienced aquarist, being considered an accessible substitute for the Asian arowana
, which is listed on CITES Appendix I and is therefore difficult and expensive to obtain legally.
is important. The minimum recommendable tank size for one adult Silver Arowana is 300 gallons (8'X3'). At no time should an arowana be kept in a tank that is narrower and shorter than the length of the fish! A young specimen can be kept in a smaller tank, but as it grows a larger tank will be necessary to prevent deformities and to ensure the maximum length and life span of the animal.
Any aquarium housing an arowana should be tightly covered because of these fishes' jumping behavior.
s. Commercially available black water additives can help simulate the Silver Arowana's natural habitat
, although they can adapt to most water supplies and thrive. A 25-30% water change, siphoning waste and other detritus
, is necessary 1-2 times every week to maintain excellent water conditions. The water temperature should range from 24°C (75°F) to 28°C (82°F), with the ideal about 26°C (79°F).
Many aquarists recommend against live feeder fish because these are often raised in poor conditions and are capable of transmitting diseases to predatory fish. Other risks include injury to the Arowana either while attempting to catch the feeder fish, or while swallowing. Mealworm exoskeletons are sometimes difficult for young Arowana to digest, so they are best avoided.
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
bony fish of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Osteoglossidae, commonly kept in aquaria
Aquaria
Aquaria may refer to:*Aquarium, in the plural*Aquaria , a computer game*Aquaria , a Brazilian metal band*Aquaria, one of the Twelve Colonies in Battlestar Galactica...
. The term "Osteoglossum" means "bone-tongued" and "bicirrhosum" means "two barbels" (from the Greek language
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
).
Description
This species is found in the Amazon RiverAmazon River
The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...
basin and in the Rupununi and Oyapock River
Oyapock River
The Oyapock or Oiapoque River is a 370-km long river in South America that forms most of the border between French Guiana and the Brazilian state of Amapá...
s in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
as well as in still waters in Guyana
Guyana
Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...
.
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. It can grow to a maximum size of 90 centimetres (35.4 in). Unlike the Black arowana
Black arowana
The black arowana, Osteoglossum ferreirai, is a freshwater bony fish of the family Osteoglossidae, commonly kept in aquaria.-Description:...
, Silver arowanas have the same coloring throughout their lifespan.
The species is also called monkey fish because of its ability to jump out of the water and capture its prey. It usually swims near the water surface waiting for potential prey. Although specimens have been found with the remains of birds, bats, and snakes in their stomachs, its main diet consists of crustaceans, insects, smaller fishes and other animals that float on the water surface, for which its draw-bridge-like mouth is exclusively adapted for feeding.
Arowana
Arowana
Arowanas are freshwater bony fish of the family Osteoglossidae, also known as bonytongues. In this family of fishes, the head is bony and the elongate body is covered by large, heavy scales, with a mosaic pattern of canals. The dorsal and the anal fins have soft rays and are long based, while the...
are sometimes called Dragon Fish by aquarists because their shiny armor-like scales and double barbels are reminiscent of descriptions of dragon
Chinese dragon
Chinese dragons are legendary creatures in Chinese mythology and folklore, with mythic counterparts among Japanese, Korean, Vietnamese, Bhutanese, Western and Turkic dragons. In Chinese art, dragons are typically portrayed as long, scaled, serpentine creatures with four legs...
s in Asian folklore.
Conservation status
The Silver Arowana is currently not listed on any CITES appendix nor on the 2004 IUCN Red ListIUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. It is one of the most popular ornamental fish from South America, however, and therefore its conservation status
Conservation status
The conservation status of a group of organisms indicates whether the group is still extant and how likely the group is to become extinct in the near future...
merits attention.
As reported by Environment News Service
Environment News Service
The Environment News Service, referred to as ENS, is an environmental news agency which provides a press release distribution service, World-Wire in addition to original stories. ENS has won many awards for outstanding journalism. It is privately owned. The Environment News Service maintains two...
in August 2005, shared use of the Silver Arowana population was a cause for a dispute between Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
ian and Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
n authorities. Juvenile Silver Arowanas are caught in Colombia for sale as aquarium fish, while the people of Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
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, on their part, would prohibit capturing them between November 1 and March 15.
The Silver Arowana is often kept as a pet by experienced aquarist, being considered an accessible substitute for the Asian arowana
Asian arowana
The Asian arowana comprises several varieties of freshwater fish in the genus Scleropages. Some sources differentiate these varieties into multiple species, while others consider the different strains to belong to a single species, Scleropages formosus...
, which is listed on CITES Appendix I and is therefore difficult and expensive to obtain legally.
Aquarium fish
Aquaria
To keep one of these large fish, a properly sized aquariumAquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
is important. The minimum recommendable tank size for one adult Silver Arowana is 300 gallons (8'X3'). At no time should an arowana be kept in a tank that is narrower and shorter than the length of the fish! A young specimen can be kept in a smaller tank, but as it grows a larger tank will be necessary to prevent deformities and to ensure the maximum length and life span of the animal.
Any aquarium housing an arowana should be tightly covered because of these fishes' jumping behavior.
Water conditions
Silver Arowana prefer soft water with a pH level between 6.0 and neutral. Strong filtration is necessary for these large carnivoreCarnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
s. Commercially available black water additives can help simulate the Silver Arowana's natural habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
, although they can adapt to most water supplies and thrive. A 25-30% water change, siphoning waste and other detritus
Detritus (biology)
In biology, detritus is non-living particulate organic material . It typically includes the bodies or fragments of dead organisms as well as fecal material. Detritus is typically colonized by communities of microorganisms which act to decompose the material...
, is necessary 1-2 times every week to maintain excellent water conditions. The water temperature should range from 24°C (75°F) to 28°C (82°F), with the ideal about 26°C (79°F).
Feeding
Silver Arowana may be offered meaty foods such as insects, shrimp, fish, beef heart, frogs, etc, though it is best to feed the Arowana a brand of floating pellet food that has been specifically processed for fish of this type. There are several types of food on the market from some of the larger name brand makers of fish products that are made with this species in mind. Feeding the Arowana in this manner will help avoid dropeye, a condition in which one of the eyes are turned downward. In the wild, the Arowana spends most of its life scanning the water surface for prey, but it will learn in an aquarium environment to look downwards for food that sinks to the bottom of its tank. Over time, one eye will permanently droop downwards. However some Arowana fed exclusively on floating food pellets have also developed sudden dropeye after violently colliding with the tank. Another condition that can develop is "cloudy eye"; one or both of the eyes become scratched when the Arowana turns itself sideways to collect food from the bottom, causing them to cloud over. The cloudy eye condition is treatable, while the drop eye condition is not. Keeping an Arowana almost exclusively on a pellet diet will not only provide the fish with a well balanced meal, it is more cost effective and will generally prevent health issues.Many aquarists recommend against live feeder fish because these are often raised in poor conditions and are capable of transmitting diseases to predatory fish. Other risks include injury to the Arowana either while attempting to catch the feeder fish, or while swallowing. Mealworm exoskeletons are sometimes difficult for young Arowana to digest, so they are best avoided.