Asian Arowana, Scleropages formosus

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

As they are native to Southeast Asia, Asian Arowana inhabits blackwater rivers and slow moving water flowing through the forested swamps and wetlands. The adults feed on other fish while the juveniles feed on insects.

These popular aquarium fish have special cultural importance in areas that are influenced by the Chinese culture. The name dragonfish stems from their resemblance to the Chinese Dragon. This popularity has had both negative and positive effects upon their status as endangered species.

These fish can achieve lengths of up to 35 inches. like all Scleropages, they have long bodies; large and elongate pectoral fins; dorsal and anal fins that are located far back on the body; and a much larger caudal fin than that of their South American relative, the Silver Arowana, Osteoglossum bicirrhosum. The mouth is oblique with a very wide gape and the prominent lower jaw has two barbels at the tip. The gill rakers are stout and they bear teeth on many bones of the mouth including the jaws, palatines, vomer, pterygoids, tongue, and parasphenoid.

The scales are large, cycloid, and, in some varieties, are metallic colored with a distinctive mosaic pattern of raised ribs. The lateral scales are positioned in horizontal rows numbered from the most ventral, the first level, to the most dorsal, the fifth level, with the dorsal scales designated at the sixth level.

Unlike most fish, the arowana reaches sexual maturity rather late, after three to four years. The females produce somewhat few eggs, 30 to 100 which are rather large. After the eggs are fertilized, the Asian Arowana displays great parental care with paternal mouthbrooding. Both the fertilized eggs and the larvae are brooded within the male’s mouth.

Image Caption: Super red arowana. Credit: Wikipedia (CC BY-SA 3.0)