Picture by: Yorkshire
Silver arowana (Osteoglossum bicirrhosum)
This profile is based on personal as well as general information. There is so much to tell about this family of extraordinary fish and particular the arowana, that it is impossible to cover all aspects. If you have any amplifications or want to know something about this beautiful specie, just ask.
The silver arowana or osteoglossum bicirrhosum belongs to the order of Osteoglassidae. To this order belongs big fish, that are living just beneath the water surface. This is also visible at the way the fish belonging to this family are evolved. These fish will often gather in huge shoals and can found in a widely distributed region, like Southern America, Africa, Australie and parts of Asia. Some of the Asian arowana's are on the CITES list of endangered species.
The allied of the Osteoglossidae are distinctive by certain characteristics of evolution, such like an extra respiratory organ. The Arapaima gigas is a good example of a fish with this respiratory organ and will use his swim bladder to breath. The arapaima is also the biggest fish of this order and is with his maximum length of 3 metre one of the biggest freshwater fish in the world.
The silver arowana
The silver arowana can be found in a widely spread natural range which runs from the north of South America to Guyana and the basin of the Amazon river, whereby the arowana especially can be found in slow floating and stagnant waters.
In the wild these fish can reach a maximum length of 120 centimetre or 48'' but will stay considerably smaller in the home aquarium and will most likely reach a length of 80-90 cm or 32''- 36''.
Their diet can consist about small life food such, like fish. My own experience was that live crickets, grasshoppers, worms and frozen artemia were greedily accepted. At the present there are also special developed arowana sticks available which will make a good and healthy addition to their diet.
Due to the potential size of this fish a (very) big aquarium is a must, whereby the dimensions must be big enough for the arowana to turn comfortably. Hereby I think that a tank with the dimensions of 200x75x50 cm or 80x30x20'' (LxWxD) is the bare minimum for an adult animal. But here goes: the bigger, the better!
It is important to have a strong lid on your tank, cause arowana's are notorious jumpers. In the wild these fish can jump as high as 5'! out of the water to grab insects and small birds that are sitting at branches hanging above the water.
Some of the fish that are compatible with the arowana are rays, pacu's and big South American cichlids. Smaller fish will be eaten without hesitation.
These fish aren't demanding regarding to plantation or other decorations. However my personal experience was that my arowana felt more comfortable with a planted bottom, whereby I had planted the bottom surface with a few groves of robust plants.
Arowana's are mouth brooders. This means that the male hatch the fertilized eggs in his mouth for a period of two months. When the eggs had come out he will keep the young's in his mouth for another period of approximately 10 days until the young's has digested their egg sack. The egg sack is a kind of food packet which is connected to the young by a umbilicus strand. During this period the young's are very vulnerable. If you see young arowana's for sale with their egg sack still on them please don't buy them!
It is possible to keep more arowana's in a very big tank. I suggest that if you want to keep more than one arowana three is the minimum number due to chance of mutual aggression.
Tanksize: for a single adult arowana a tank with the following dimensions 200x75x50 cm or 80x30x20'' (LxWxD) is the minimum.
Size: arowana's can reach a maximum length of 120 centimetre or 48''in the wild, but will reach a length of 80-90 cm or 32''- 36'' in the home aquarium.
Temperature: 25-27 degrees Celsius.
Water quality: arowana's are sensitive fish that requires clean water. This means that a good and efficient filtration system is a must. Also be prepared to do water changes on a regular base.
Lightning: arowana's don't have specific demands for lightning, but from my own experience I know that they feel more secure when the lights are dimmed.
Health: as I already stated arowana's are sensitive fish that requires clean water. A pretty common affection these fish can develop is called droop-eye. This affection is probably caused because the fish are distracted things outside the aquarium and are often forced to grab their food from the bottom. In the wild these fish are used to grab their prey at and above the water surface through which they necessarily must look on high.
An other pretty common affection for arowana's is gill curling. This is caused by a too high concentration of ammonia, nitrite or nitrate.
Summing up I can say that arowana's are beautiful fish with a matching personality. The way that they will constantly 'float' through the aquarium gives them almost something majestic. However arowana's are sensitive fish and require optimal circumstances. If you have created the right circumstances you can be sure that the arowana is a very rewarding fish to own.