Common Name: Silver Arowana
Family: The silver arowana along with its relatives are located in the family Osteoglossidae. The genera of Osteoglossidae are: Arapaima, Osteoglossum, Heterotis, and the Sceropages. The silver arowana is located in the genera Osteoglossum, along with the black arowana (Osteoglossum ferreirai).
Origin: The silver arowana of South America can trace its origins backs to the Eocene Period (35 to 55 mya) and is the most common arowana that appears in the aquarium trade. Survival was what these fishes were built for. Also the name Osteoglossum means "bony tongue" and it refers to the bony tooth-like structure located on the bottom of the mouth. When this tongue is pressed against the roof of the mouth, it helps hold prey and shred it.
Location Found: Silver arowanas are usually found in the Amazon River Basin in South America.
Confusion: The silver arowana is usually confused with its close relative the black arowana because it has the same appearance is the silver arowana. The difference is that the black arowana is a slimmer fish in relation to its body depth. Adult silvers tend to be pinker overall, including its fins. But in the black arowana it’s anal, caudal, and dorsal fins tend to be much darker. Another way to tell them apart is when they are young. When the black arowana is young it is almost literally black wit ha very distinct yellowish-cream longitudinal band stretching form behind the head to the tip of the caudal fin. Also young black arowanas have a vertical yellowish-cream band immediately behind each gill cover. Young silver arowanas on the other hand also have vertical and longitudinal bands but colors are way more subdued than the black arowana.
Description:The arowana’s body shape and structure is adapted to a life at the surface of the water column. Because of its large eyes on the side of its head, it is identified as a visual hunter. Light, shadow, and movement are what the arowana depends on to find its prey. The mouth of this predator is constructed for nipping prey from the water’s surface, in which its mouth opens almost vertically. Also on its upward pointing mouth it has two chin barbels. The body is an elongated, sinuous body with a straight dorsal profile. The arowana’s oar-like tail and streamline body makes it an extremely fast and efficient swimmer, helping it escape would-be predators and capture fleeting prey. The color of a typical silver arowana is silver with pinks and greens on the scales and fins.
Size: The usual size of the silver arowana is 30in. in the aquarium and in the wild they have been known to reach an amazing 48in.
Growth Rate: Most silver arowanas grow an inch a month if feed properly.
Lifespan: Most arowanas can live up to be 10 years and older if well cared for. Some say it can even live up to about 50 year old.
Sexing: There is no way to sex the silver arowana 100% because it has no physical characteristics that shows any differences. Some say that the males have a large under bite and a long anal fin, but no one knows for sure. The only true way to tell is if a pair is formed and they breed.
Tank Requirements: Silver arowanas in the aquarium trade demand very large aquariums and high standards of water quality. A 7x3x2ft tank would be the absolute minimum for housing an adult arowana for life. If the aquarium is going to be planted it will need to have ample swimming space for the arowana. Also the surface should have at least half of it open so that the arowana can feed. Some floating plants are beneficial especially for the young arowanas because they seek shelter under them. But a bare tank will do fine, as long as it has nothing in there that can injure the arowana. Also young arowanas can be started in a 10 gal but will have to be upgraded in to a larger aquarium as it grows.
Temperature: The temperature of the tank should be from 74 to 86 degrees. Temperatures over 86 degrees should not be maintained.
Water Quality: The pH of the tank should be from 6.2 to 7.2 and offer the utmost biological and chemical filtration. Because without this the arowana’s long, delicate anal fin and barbels are subject to fin rot and degrading conditions when exposed to inferior water quality. Weekly water changes of 25% or more is essential to the long term health of the arowana.
Diet: Silver arowanas will take almost anything you put in its tank, as long as it can fit in its mouth, like fish, insects, birds, rodents, etc… Young arowanas should be started with small crickets, disease free feeder fish or if it will take it, frozen blood worms or brine shrimp. But as the arowana gets older it should be weaned off of feeder fish and on to pellets, frozen foods, and foods with a higher nutrition value. The weaning process will take a little time, some patience, and some effort for it to work.
Breeding: Silver arowanas along with similar species are usually mouthbrooders, and the male is usually the brooder of the large eggs. The size of the eggs can vary from .8cm to 1.8cm. Arowanas are not known to breed in the home aquarium but can be done if a large enough aquarium is provided. The only way to get them to breed is by letting the adults form pairs. A group of four or more is the best was to acquire a pair and usually guarantees at least one pair. Once the pair is formed the pair will swim side by side for a month or so before breeding. Once the pair has bred the male will brood the eggs for about 40 to 60 days before releasing them. Also the breeder can strip the brooder of the eggs to speed up the process to get another batch of eggs. Once the male releases the young they are approximately 3 to 4in each. In a single batch the average egg count is anywhere from 6 to 30 eggs.
Temperament: Usually silver arowanas cannot stand each other but a group can usually be maintained together.
Tank Mates: Fish large enough that well not fit in the arowanas mouth will make a great tanks mate. Large catfishes and plecos make perfect tank mates.
My Experiences: Right now I have a young 10in silver arowana in a 75gal tank. Once it out grows this tank I am going to build a wooden 8x8x4ft tall pond for it. His diet is Hikari Food Sticks along with the occasional large feeder. My water parameters are 6.2 pH, 0 GH, 0 kH, 0 NH3, 0 NO3, and 0 NO2.
Edited by Louie_hawj, 16 April 2007 - 02:27 PM.