The Arowana or Silver Arowana is related to early primitive fishes and is sometimes called the "Bony-tongued Fish".
One of the most interesting fish, the Silver Arowana gets rather large. A 47 inch specimen, although rare, will need an aquarium of at least 100 gallons just to turn around! Though they can be kept together when small, larger specimens are best kept singly or with other species of larger fish. They are a predator and will eat small fish. But on a positive note, they can become quite tame and take food from your fingers.
These fish are excellent jumpers so make sure the top of the aquarium is covered. The Arowana will prefer an aquarium with a fine gravel bottom planted loosely with hardy plants and open areas on the top to swim.