Silver arowana

Appearance

This species is found in the Amazon River basin and in the Rupununi and Oyapock Rivers 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 . 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 drawbridge-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 dragons in Asian folklore.

Status

The silver arowana is currently not listed on any CITES appendix nor on the 2004 IUCN Red List. 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 Brazilian and Colombian authorities. Juvenile silver arowanas are caught in Colombia for sale as aquarium fish, while the people of Brazilian 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, which is listed on CITES Appendix I and is therefore difficult and expensive to obtain legally.

Food

Silver arowana may be offered meaty foods such as insects, shrimp, fish, frogs, pellet foods, etc., though it is best to feed 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 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.