Australian Arowanas have seven layers of scales on each side compared to five of the Asian Arowanas. The Leichardti has spots on each scale and fins hence the common name, Spotted Arowana.
The Jardini (Pearl Arowana) on the other hand is often passed off as an Asian Arowana since little difference may be seen at their early stages (between 0-8 months) and sold for a lot more than it's worth.
SO be very very careful
Actually there are a few types of Spotted Arowanas. They are originally from Australia (also known as Australian Gold, Aus-Pearl Arowana, Northern or Southern Barrumundi).