The Asian arowana (Scleropages formosus) comprises several phenotypic varieties of freshwater fish distributed geographically across Southeast Asia.

Native to Southeast Asia, Asian arowanas inhabit blackwater rivers, slow-moving waters flowing through forested swamps and wetlands.

Like all members of the Osteoglossidae, Asian arowanas are highly adapted to fresh water and are incapable of surviving in the ocean.

Therefore, their spread throughout the islands of Southeast Asia suggests they diverged from other osteoglossids before the continental breakup of Pangaea was complete.

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 Scleropages species shows little evolutionary change has taken place recently for these ancient fish.

[12][13] Several distinct, naturally occurring colour varieties are recognised as haplotypes, each found in a specific geographic region.

Asian arowanas bear teeth on many bones of the mouth, including the jaws, vomer, palatines, pterygoids, parasphenoid, and tongue.

[8][14] Asian arowana scales are large, cycloid, and, in some varieties, metallic-coloured, with a distinctive mosaic pattern of raised ribs.

[8] Mature red-tailed golden arowanas have brilliant metallic gold lateral scales, gill covers, bellies, and pectoral and pelvic fin membranes, although the back is dark.

"[16] In Taoist divination, positive feng shui associations with water and the colours red and gold make these fishes popular for aquaria.

For example, Asian arowanas are now uncommon in the Malay Peninsula, where they were once widely distributed, due to environmental destruction.

[14] Inclusion in the IUCN Red List was originally based not on biological reasons but on practical ones: though widely distributed throughout southeast Asia, they have been harvested heavily by aquarium collectors.

Additionally, considering the current confusion as to number of species, as well as the wide distribution, conservation status should be reconsidered.

[7]Beginning in 1989, CITES began allowing Asian arowanas to be traded, provided certain criteria were met, most notably that they were bred in captivity on a fish farm for at least two generations.

[24] Later, the Singapore government's Agri-food and Veterinary Authority (then called the Primary Production Department) and a local fish exporter collaborated in a captive breeding program.

Second, each specimen receives an implanted microchip, called a passive integrated transponder, which identifies individual animals.

Examples of appropriate live foods include scorpions, centipedes, mealworms, crickets, shrimps, feeder fish, small frogs, and earthworms.