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.
The Arowana Osteoglossum bicirrhosum was described by Cuvier in 1829. The Greek terms "Osteoglossum" means "bone-tongued" and "bicirrhosum" means "two barbels". So this fish is basically described as a Bony-tongued Fish with two barbels. Other common names they are known by are Silver Arowana, Bony-tongued Fish, Silver Arawana, Silver Aruana, Silver Arrowanas, Dragonfish, and Water Monkey. The species is not listed on the IUCN Red List.
The Silver Arowana are found in white and black water floodplains of South America. They can also be found in the Amazon River and Basin, Rupununi and Oyapock River. They cannot travel upriver however, because they can't swim through the rapid moving waters. They prefer the very calm waters in swamps and shallow flooded areas. They have been introduced into the United Sates in California and Nevada. This is not their natural habitat, rather they were released by irresponsible fish keepers that could not meet their unique needs.
In nature the Arowana will eat just about anything that will fit into its mouth. Their diet mainly consists of fish, but also insects such as water fleas, and insect larvae. They will also eat plant matter but this is a small part of their diet. They are known to actually jump out of the water and grab a bird if they have the opportunity. They have found snakes, monkeys, turtles, and rodents in the stomach of these fish.
The Arowana is a very important fish to the economics and health of the people that live in its territory. These fish are in great demand and bring a good amount of money to the local fishermen. The Arowana have a very low fat content and are the least likely of fish to cause stomach issues due to indigestibility. It is also a recommended fish for pregnant and breastfeeding woman to eat. The locals also profit from catching these fish to sell to the aquarium business.
Scientific Name: Osteoglossum bicirrhosum
Social Grouping: Solitary
IUCN Red List: NE - Not Evaluated or not listed
The Arowana is a very big fish that can reach up to 47.24 inches (120 cm) in length. However they are smaller in the aquarium usually reaching about 24 to 30 inches (60 - 78 cm). This is a long fish with a lithe, fluid swimming motion that makes it seems almost snakelike.
As its common name suggests, it is silver colored fish. However it has large opalescent scales that reflect blue, red, and green highlights as the fish grows older. This beautiful coloration is where they get their nickname Dragonfish in the wild. There is also an albino color morph, which though much more rare, is truly a beauty.
The mouth is at the top of the body and opens in three pieces to be able to take in and swallow large prey. These fish are known for their bony tongue. Many of their oral bones are covered with teeth which include the jaw, palate, tongue and pharynx. There are two barbels at the tip of the lower jaw used as sensory devices to sense and capture prey.
It eyesight is very keen, allowing it to see above the surface, spotting and leaping out of the water to strike insects from over hanging tree branches. The Arowana can also breathe air via their swim bladder.
Size of fish - inches: 47.2 inches (119.99 cm)
Lifespan: 20 years - Can have a life span 10 to 20 years in a well maintained aquarium.
Fish Keeping Difficulty
The Silver Arowana is not a fish for the beginner. They need a ton of space, even a young Arowana will need space because they grow so fast. A juvenile needs at least a 55 gallon tank, but a 300 gallon to tank will soon be needed to accommodate these monster fish. These fish need very clear and clean water too. However as with most fish that inhabit rivers and swamps, they are very tolerant to changes in pH and water hardiness. It can also be expensive to feed these fish. Because of their size they need much more food then your average fish.
Aquarium Hardiness: Moderately hardy
Aquarist Experience Level: Advanced
Foods and Feeding
The Arowana are omnivores with a natural diet that mainly consists of fish, but also insects such and insect larvae. They will also eat plant matter but this is a small part of their diet. They are also known to eat just about anything in the wild that fits in their mouths including birds, snakes, monkeys, turtles, and rodents.
In captivity the Silver Arowana will generally eat all kinds of live foods. They are generally fed night crawlers, red worms, mosquito larvae, feeder fish, shrimp and most anything else nutritious that they can fit into their mouths. Sometimes they will accept large flakes or pellets which is desirable in order to give them a balanced nutrition. They greatly prefer fishes that can be swallowed whole, but can be trained to take pieces of raw fish, shrimp, and other meaty foods from the fingers.
Diet Type: Omnivore
Flake Food: Occasionally
Tablet / Pellet: Occasionally
Live foods (fishes, shrimps, worms): Most of Diet
Vegetable Food: Some of Diet
Meaty Food: Most of Diet
Feeding Frequency: Daily - This depends on what you are feeding. Arowana pellets can be given daily.
The Arowana tank needs to be very large with clear, clean water. They create a lot of waste due to their size and require ammonia and nitrites to be at zero. A large canister filter is a must with these fish. A 50% water change should be done weekly.
Water Changes: Weekly - Water change should be 50% weekly
These fish will swim in the top of the aquarium.Depth is not real important to them, but length and width are very important. These fish get very long and need to be able to completely turn around unobstructed. A 55 gallon aquarium is minimum for a juvenile, but you will need at least a 300 gallon tank as this fish grows. This fish is a powerful jumper so a very tight secure lid is necessary. Decor isn't important below the fish. The Arowana will appreciate some branches above the water line to break up the lid and light.
The Arowana enjoys calm slow moving waters and a strong filter is needed. To accomplish this make sure to have the water outflow tube hanging lower in the tank, closer to the bottom. A fish tank light that has different lighting that will slowly dim before going out will help reduce chances of startling the fish, causing it to jump and becoming injured. Its also a good idea to set this tank up where it can get a couple hours of sunlight a day. A large pleco will be helpful to cut down on algae growth.
Minimum Tank Size: 55 gal (208 L) - A 55 gallon tank will work for juveniles, but at least 300 gallons will be needed for an adult.
Suitable for Nano Tank: No
Substrate Type: Small Gravel - Dark gravel is preferred.
Lighting Needs: Moderate - normal lighting - Be careful of sudden lighting changes. This can startle the Arowana and may cause it to jump and possiblly injure itself.
Temperature: 75.0 to 86.0° F (23.9 to 30.0° C)
Range ph: 6.5-7.0
Hardness Range: 8 - 12 dGH
Water Movement: Weak
Water Region: Top - The Silver Arowana will swim in the top of the aquarium.
They are generally not a good community fish. Only small specimens can be kept together and with other fish. As they get older their size and the fact that they eat other fish makes them unsuitable for any but the largest of tank mates.
Same species - conspecifics: Yes - These are solitary fish that only appreciate company as juveniles, adults may show excessive dominance and aggression unless there is enough room not to crowd each other.
Peaceful fish (): Monitor - Only if large enough not to fit in their mouth.
Semi-Aggressive (): Monitor - Only if large enough not to fit in their mouth.
Aggressive (): Monitor - The Arawana is generally tolerant of other large species.
Large Semi-Aggressive (): Monitor
Large Aggressive, Predatory (): Monitor
Slow Swimmers & Eaters (): Monitor - Only if large enough not to fit in their mouth.
Shrimps, Crabs, Snails: Threat - is aggressive
Sex: Sexual differences
The male is more slender and has a longer anal fin.
Breeding / Reproduction
Water parameters for breeding the Arowana or Bony-tongued Fish are the same as for general maintenance above. Feed large amounts of live food to induce spawning. The eggs are up to 1/2 inch in diameter. The male will brood them in his mouth. After 50-60 days the eggs will develop and produce fry which have and obvious eggsak. They are 3-4 inches long before this is gone and they will feed entirely on their own.
Ease of Breeding: Difficult
The biggest issue that most fish keepers have with the Arowana is injury caused by not enough room in tank to turn. In tank the Arowana will tend to get dropeye from looking for food on bottom of tank instead of top. This also happens from rapid collisions with tank. This can be prevented by having colorful balls floating on surface to keep them looking up. Cloudy eye is another condition that develops from the fish turning sideways to eat and scratching its eye. Cloudy eye is treatable whereas dropeye is not, dropeye if preventable though.
As with most fish the Arowana are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. Anything you add to your tank has the possibility of bringing disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance.
These fish are hardy and disease is not usually a problem in a well maintained aquarium. That being said there is no guarantee that you won't have to deal with health problems or disease. Because these fish eat live food, disease can be passed to them from their foods. Make sure to quarantine live food before feeding.
A good thing about the Arowana is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your fish the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. I stressed fish will is more likely to acquire disease.
Knowing the signs of illness, and catching and treating them early makes a huge difference. It is recommended to read up on the common tank diseases. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
The Arowana or Silver Arowana is available from time to time.
Nick Takhar - 2016-07-18 I have a 4ft x 2ft complety round fish tank 156 gallon I have but two 5 inch Silver arowana in the tank Does That give them more space to swim around because it' a round tank or I still have to get a bigger tank and also do they fight at the beginning then they sort them selfs out Any help will do thank you
Samuel - 2005-07-01 I came home one day and my Pleco was bleeding from the mouth. My only other fish is my arowana...he is loyal and lets me pet him! I love my fish and will stay a loyal arowana owner!
Tina - 2014-10-22 Hi everyone! I just had to share my story with other Arowana enthusiasts. I'm discovering mine is letting me 'pet' it. Yes...I did say pet it! It's AMAZING! I have a pretty big tank 55 gal...with other beautiful freshwater fish. They all live in harmony & I call it my 'Happy Tank'. I love them all...they're my family! BUT...I must say...I'm smitten w/ my Wana...whose about 14-15 inches now. It started about a couple of weeks ago. I just slightly & lightly would take my forefinger & middle finger @ let it 'slide' through my fingers. What an incredible feeling! Lately...it's letting me hand glide its body. It doesn't freak out & keeps turning back for more! Anyone else have such a great experience? And...who says fish can't be great pets?!? :-)))
Courtney - 2015-05-04 My boyfriend has an arowana and it lets me pet it too! I absolutely love it! It's so strange though, It will not let him pet it ( him being the owner and care taker of the fish for the past two years), but will let me pet it with no issues. Has anyone ever had this issue? We believe it is because he is a male and i am a female but we are unsure. As all the research we have done on the fish we are unable to determine the sex.