Arowana Fish Species Profile

Silver arowana

Getty Images/HuyThoai 

Intro

Species Overview

Common Name: Arowana

Scientific Name: Osteoglossum bicirrhosum

Adult Size: 3-4 feet

Life Expectancy: 10-20 years

Family Osteoglossidae
Origin Columbia, Peru
Social Aggressive
Tank Level Top-dweller
Minimum Tank Size 300 gallons
Diet Carnivore
Breeding Mouth brooder
Care Advanced
pH 6.0-7.0
Hardness dGH 1-8
Temperature 75 to 85 F (24 to 29 C)

Origin and Distribution

The Arowana is a freshwater fish of the ancient ray-finned fishes, the Actinopterygii. There are many families of Arowana, originating from South America, Africa, Asia and Australia. The familiar Silver Arowana (Osteoglossum bircurrhosum) diverged from their Asian and Australian cousins (Scleropages spp.) during the Jurassic period.

In the pet trade, there are 10 varieties of arowana that are classified by their origin. Arowanas of the species Scleropages formosus (Asian bonytongue aka Green Arowana) and Sclerophages inscriptus (Myanmar bonytongue aka Scripted Arowana) are endangered and listed as CITES level I, requiring a special permit and are threatened with extinction.

Some arowanas can be very expensive pet fish. There are reports of some varieties selling for >$100,000 per fish. There are some states that do not allow the shipment of Arowana due to its potential threat to native species if it were to be released.

Colors and Markings

The various Arowana varieties are commonly classified by their origin and coloration. The common Silver Arowana is a pale silver to gold. Juveniles may have a blue tint and a yellow-orange bar along their side. Other species may be tinted red or green, depending on their species.

All arowana have very large scales with a pair of barbels on their lower jaw. The dorsal and anal fins are almost fused with the tail, giving the fish a streamlined appearance.

Tankmates

No matter what variety, arowana are solitary fish. Unless you have a VERY large system and are planning on breeding arowana, only one fish is recommended.

Unfortunately, some arowana are very picky eaters and refuse to eat anything other than live feeds. Try to avoid this if you can. Keep in mind that any live fish or invertebrates entering the aquarium should be quarantined prior to being fed. If your arowana decides they are not interested in the live feed at that time, you may need to consider long term care of those additions.

Arowana Habitat and Care

Arowana can grow exceptionally large, even though they start deceptively small. You will require at least 300 gallons per fish. It is recommended to go bigger if you can and make sure you have a solid lid. In the wild, arowana are used to jumping for their food, so they may try to unwillingly escape if they see a bright light or a reflection on the top of their tank. A wider, shallower tank will prevent your fish from getting too much momentum towards the surface. Some owners will have a collar of plexiglass or netting around the top of their tank with a side door in order to access the water surface. This will allow your fish to hunt naturally while not flying out of the aquarium!

Keep your arowana tank free of obstructions. They are quick to charge their food and may be hindered by lots of decor items. Do not expect live plants to do well in arowana tanks without supplementation since there is only one fish in a large volume of water, unable to produce adequate levels of nitrate.

A common complaint in arowana is a "droopy eye." This occurs when an arowana has to do all their hunting from above, rather than below, like their wild counterparts. Arowana are surface sight hunters, so without anything to hunt on the surface, their eyes start to drift downwards. Many hobbyists attempt to surgically correct this by removing the retrobulbar fat pad around the dorsal aspect of the eye. First: never attempt surgery on your fish without the proper training. Only use a trained veterinary professional. Often, these surgeries are only a temporary fix, since your fish will continue to hunt below them, now less successfully. Instead, give your fish something on the surface that catches their interest. Frozen food items or pellets coated in oil to give them a more reflective surface are some good ideas. Remember, they might try to jump for whatever is on the surface!

Arowana Diet and Feeding

Arowana are on the carnivorous fish feeding spectrum. Their wild counterparts are known for grabbing prey off the surface of the water, a hard lifestyle to replicate in an artificial environment. If possible, allow your fish to hunt their meals at the surface. See above section for creating a safety or access zone above your aquarium.

It is best to feed your arowana a pelleted diet with meaty supplements, such as krill and shrimp. Do not introduce live feeds if your fish is willing to eat pelleted diet. Many hobbyists have made this mistake and the fish will refuse to go back to the pelleted diet. It may be "fun" or "natural" for your fish to hunt wild prey, but it could potentially be bringing in disease and is certainly not a fun experience for the intended prey.

Gender Differences

There are no external differences between male and female arowana. This is one of the biggest challenges when attempting to breed these fish. It is thought that the male mouth might be slightly larger with fish of the same age and size, but this has not been verified.

Breeding the Arowana

Arowana are mouth brooding fish, wherein the male will carry the unhatched eggs in his mouth. During this time, the males will not eat. They will carry the eggs for 50-60 days until the eggs hatch into fry.

More Pet Fish Species and Further Research

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