[2] In this family of fish, the head is bony and the elongated body is covered by large, heavy scales, with a mosaic pattern of canals.

[4] The Osteoglossidae are the only exclusively freshwater fish family found on both sides of the Wallace Line.

Other fossils from as far back as the Late Jurassic or Early Cretaceous are widely considered to belong to the arowana superorder Osteoglossomorpha.

The young may make several tentative trips outside the parent's mouth to investigate the surroundings before leaving permanently.

Unlike most fishes that start reproducing at around six months of age, the arowana usually takes three to four years to reach sexual maturity.

Depending on the classification system used, there are ten types of arowana commonly kept as pets: four from Asia, three from South America, two from Australia, and one from Africa.

These fish are best kept with live or frozen feed and they easily outgrow the tank within eight to ten months.