Arowanas, also known as "dragon fish", from the family Osteoglossidae, are magnificent freshwater fish that somehow look prehistoric. They have a bony protrusion inside their large mouth which is why they are also known as "bone-tongues". This bone tongue is used by the fish to further emaciate its food by grinding the tongue against the teeth that are in the roof of the fish's mouth. Arowanas usually grow to around 3 to 4 feet in length in captivity but there are reports that they can grow up to 8 feet or 2m in the wild. There are only six known species of Arowana in the world, mainly found in South America, Australia, Africa and Asia.
Another interesting fact about the Arowana is that it's a part-time air breather, meaning it can absorb oxygen from the air if the water has low levels of oxygen. The fish does this by sucking air into its swim bladder, which is full of capillaries much like the lung tissue of mammals.
Arowana fish have a rapid growth cycle, often reaching lengths of 17-23 inches by the time they are 3 or 4 years old. By this time the fish may be a bit mature already so the differences in gender may be obvious. The males have a shallower body, larger head and mouth, and a longer tail than the female Arowana. Males are also more brightly colored than the females and are also more competitive when it comes to food and territory.
Being a natural predator, the Arowana generally eats any living thing that can fit into its large mouth. The Arowana feeding habit is usually constituted of small fish, frogs, and insects. But there are reports that the Arowanas can leap clean out of the water and devour perched birds and even the occasional bat or two, this is an easy feat for this very powerful fish.
The Arowana is a very popular fish among aquarium enthusiasts, especially the Asian variety. The Asian species of Arowanas have the brightest coloration of all the known species. The most popular is the Golden Arowana, which has shimmering scales that look like they might actually be made of gold. But the rarest, and most expensive, is the Super Red Arowana, which has a deep, blood-red color.
The Arowana is prized not only for its beauty, but also for their believed mystical attributes as well. In most parts of Asia it is believed that the Arowana carries good fortune, due to its resemblance with the mythical dragon.
The Arowana truly is a remarkable fish, truly deserving the title of "King of the Aquarium".