The Arowana Osteoglossum bicirrhosum was first introduced into the aquarium hobby in 1912. This fish provides us with a glimpse into the past. It is one of only a few living examples of our ancient prehistoric world of the Jurassic age. Its scientific name is derived from the Greek terms "Osteoglossum" which means "bone-tongued" and "bicirrhosum" which means "two barbels". So basically this as a bony-tongued fish with two barbels. Because of its coloration it is also known as a Silver Arowana. It has a few different spellings, so it can be found as a Silver Aruana, Silver Arawana, and Silver Arrowanas. But all these common names are representative of the same species.
The Silver Arowana is one of the most interesting fish and it can get very large. It is a long fish with a fluid, almost snake-like swimming motion. A maximum sized specimen would reach up to 47 inches (120 cm) in length and need an aquarium of at least 4 feet wide and 4 feet long just to turn around. A specimen of that size is pretty rare in the aquarium, generally they are smaller with 24 to 30 inches (60 - 78 cm) being a good sized Arowana. It is basically a silver fish, but its scales are very large. As this fish matures the scales develop an opalescent effect that will reflect blue, red, and green highlights. This has led to the nickname "Dragonfish" when seen in the wild.
One of the most curious characteristics of this fish are its mouth. It opens in three pieces and looks similar to a loading barge, definitely indicative of its predatory nature and appetite. The two distinctive barbels at the tip of the lower jaw are great sensory devices. With them, it can sense and capture prey on the surface of the water, even in total darkness. Its eyesight is also remarkable. With a keen vision, this fish can see above the surface, spotting and leaping out of the water to strike insects and birds from over hanging tree branches. This has lead to still another nickname for this fish, the "Water Monkey".
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 and very strong, so make sure the top of the aquarium is securely covered. The Arowana will prefer an aquarium with a fine gravel bottom, planted loosely with hardy plants, and have open areas on the top to swim.
suitable tank size for arowana :
The most important condition to be observed to keep arowana fish in a tank is the size of this tank. Recommended tank capacity must be over 500 liters (132 gallons).
For arowana fish the Minimal tank size is 160 cm long, 60 cm wide and 50 cm high.
the Ideal tank size for arowana has to satisfy the formula of : the tank length has to be at least 3 times larger than the fish length and the tank width should be not less than 1.2 times of the fish size.
It’s acceptable to keep young arowana in smaller tanks temporary, however, later the fish must be taken into a proper sized tank to avoid the fish body deformation and to insure the fish maximum life span and body length.
The tank has to be securely closed with some glass from the top to prevent the fish from jumping out of it.
The fish requires strong water filtration, 25-30% of water, and weekly tank cleaning to keep the proper water characteristics. arowana prefers soft water with pH value from 6.0 up to neutral.
Tank water temperature should be from 24 to 28° С (75-82F), ideally it should be close to 26°С(78F).