Like all Scleropages, Asian arowanas have long bodies; large pectoral fins; dorsal and anal fins located far back on the body; and a much larger caudal fin than that of their South American relative, the silver arowana, Osteoglossum bicirrhosum. Their scales are large and, in some species, metallic colored. The scales have a distinctive network of raised ribs. These mouthbrooding carnivores have paired barbels on the end of the lower jaw.
All Asian arowanas are distinguished from Australian congenerics S. jardinii and S. leichardti by having fewer (21-26) lateral line scales (versus 32-36), longer pectoral and pelvic fins, and a longer anterior snout.
The Asian arowanas are listed as endangered by the 2006 IUCN Red List, although it was last evaluated in 1996. International trade in these fishes is controlled under the Convention on the International Trade in Endangered Species of Wild Flora and Fauna (CITES), under which it was placed on Appendix I, the most restrictive category, in 1975. There are twenty three registered CITES breeders in Asia and the specimens they generate can be imported into several nations, although not the United States.
Fresh water fish
Asian arowanas are prized aquarium fish in some parts of the world, and the various color varieties have differing values to hobbyists. The super red arowana is regarded by many to be of greatest beauty because red is considered an auspicious color, according to some local cultures (see Cultural Beliefs below). Each color variety has variations among different localities. For instance, the gold crossback may have various base colours, including blue, gold, green, turquoise, and purple. Hobbyists consider the highest grade of the gold crossback to be the full gold crossback (frameless gold), which originated from the Sungai Gedong river system.
These popular aquarium fish have special cultural significance in areas influenced by Chinese culture. The name dragon fish stems from their resemblance to the mythical Chinese dragon. This popularity has had both positive and negative effects on their status as endangered species.
All osteoglossids are highly adapted to freshwater and are incapable of surviving in the ocean; therefore, the spread of Asian arowanas throughout the islands of southeast Asia suggests they diverged from other osteoglossids before the continental breakup was complete. Confirmation has come from genetic studies, which have shown that the ancestor of the Asian arowanas diverged from the ancestor of the Australian arowanas, S. jardinii and S. leichardti, about 140 million years ago, during the Early Cretaceous period. This divergence took place in the eastern margin of Gondwanaland, with the ancestors of Asian arowanas carried on the Indian subcontinent or smaller landmasses into Asia. The morphological similarity of all six species shows that little evolutionary change has taken place recently for these ancient fish.
Young Silver Arowanas should not be overfed, because according to some hobbyists, they can develop dropeye, a condition in which the eyes are turned downward, as they grow. Arowanas should be offered meaty foods such as insects, shrimp, fish, beef heart,