Silver Arowana 101: Care, Size, Tank Mates & More!

The Silver Arowana is a large and beautiful freshwater fish that has quite a reputation in the aquarium community.

While many aquarists are intimidated by this species, others view ownership as a challenging and rewarding next step in their fishkeeping progression.

If you’re in the second group then you’ve come to the right place. This guide will teach you the fundamentals of Silver Arowana care to make sure you’re up to the task.

Not only will it prepare you for ownership, but it’ll help you get a better idea of what owning one of these massive fish really looks like.

Species Summary

The Silver Arowana (Osteoglossum bicirrhosum) is one of the most sought-after fish in the aquarist community. For many, it’s considered to be the pinnacle fish of the hobby. These freshwater fish are absolutely stunning, but they are not for the faint of heart!

A full grown adult Silver Arowana

Hailing from the Amazon River Basin in South America, these fish are revered for their looks and predatory behavior. Often referred to as Dragon Fish or Monkey Fish, Silver Arowanas are highly aggressive fish and have some demanding care requirements.

They are not a good fish for beginners by any means. To keep them healthy, you must provide Silver Arowanas with a heavily controlled environment and plenty of high-quality foods.


The average Silver Arowana lifespan in captivity is somewhere in the 10 to 15-year range. Getting one of these fish is a serious long term commitment.

While the lifespan of every species can be affected by things like water conditions, environment, and diet, it’s especially true with Silver Arowanas. These fish are prone to experiencing developmental issues that could shorten their lifespan dramatically.

To give your fish a healthy and stress-free life, you’ll need to be vigilant about their care and the kind of habitat you provide.


Silver Arowanas belong to a special group of fish species called “band fishes.” When you take a look at the Silver Arowana, it’s not hard to see why they have this name.

They have long and slender bodies. While their bodies do taper off towards the tailfin, it’s not nearly as dramatic as some other species. Thus, they take on a band-like shape.

From the side, the fish look very flat. However, when you look at them head-on, you’ll notice that they do have considerable girth.

The most defining feature of Silver Arowanas is their fins. The dorsal and anal fins stretch all the way down to the tailfin, which is surprisingly small. The tailfin is considerably smaller than what you would expect to see on fish of this size.

Because the dorsal and anal fins extend down most of the body, most don’t even realize how small the tailfin is. In fact, it appears to be connected at first glance. It’s only upon closer inspection that you can see a very minute gap separating the tailfin from the others.

Osteoglossum bicirrhosum side profile

Silver Arowanas have thin pelvic and pectoral fins. On the head, these fish also have two distinct barbels. Located at the tip of the mouth, these barbels are what give the species its “Dragon Fish” nickname.

Another standout feature of Silver Arowanas is its mouth. It’s almost vertical and operates much like a drawbridge. The unique shape allows the fish to sneak up on prey quickly and efficiently.

When it comes to color, these fish are silverish. Large scales cover the entire body and take on a somewhat pearlescent finish. As juveniles, the scales have a slightly bluish tone, though this difference is very minor.

Males and females look remarkably similar. There are only a couple of subtle differences used to tell them apart. Typically females are a bit plumper than males. Furthermore, males tend to have a longer anal fin.


The typical size of a Silver Arowana in captivity is almost 3 feet long when fully grown! These are massive fish.

In the wild, they’re known to get even larger. Specimens that are nearly 4 feet long have been recorded.

Author Note: Size is one of the biggest obstacles that fish owners have to overcome. These fish have a very fast growth rate and can quickly outgrow small tanks.

Thus, you need a large enough tank size to support them. We’ll get into the specifics of that later on in the guide.

Silver Arowana Care

Silver Arowana care is no easy task. They can be a handful to raise due to their size and temperament. Not only that, but these fish can be quite sensitive to poor water conditions.

The key to keeping this species healthy is to mimic their habitat in the wild and stay on top of conditions. As long as you stay within a healthy range of parameters, you’ll be well on your way to keeping them in good shape.

Tank Size

The minimum tank size for a Silver Arowana should be 250 gallons for an adult. As we mentioned earlier, these fish require very large tanks to stay healthy.

Juveniles can do fine in tanks as small as 60 gallons. However, they have a very rapid growth rate. They can grow up to 2 inches a month during their first year alone!

Because of this, it’s best to just start them off in larger tanks that can support the growth.

Failing to provide your Silver Arowana with an optimal tank size can lead to a litany of problems. The fish can start to feel crowded, claustrophobic, stressed, and aggressive. They may even try to jump out of the tank (we’ve heard stories).

In the worst-case scenario, they can experience developmental issues. A lack of space can cause deformities, which ultimately reduces their lifespan.

Water Parameters

Silver Arowanas can be found in warm streams and tributaries throughout South America. Interestingly enough, they do fine living in both blackwater and whitewater environments.

While you don’t have to go so far as to replicate murkiness, you will need to pay attention to pH balance, temperature, and hardness.

The Amazon River Basin is quite warm. Waters are also teeming with life, which affects overall acidity.

Silver Arowanas are flexible enough to handle some fluctuation, but you need to make sure that measurements always fall within the following acceptable ranges.

  • Water temperature: 75°F to 82°F
  • pH levels: 5.0 to 7.5 (aim for the middle)
  • Water hardness: 1 to 8 dKH

Author Note: Because these fish can be sensitive to changing water conditions it’s important to perform regular tests with a good aquarium testing kit. Aim for a test every 2-3 days if possible.

Setting Up The Inside Of Their Tank

Generally, fish that are endemic to the Amazon River prefer lush environments filled with plants. That’s not the case with Silver Arowanas. While they do like plants, swimming space should be a priority here.

One Silver Arowana swimming in an aquarium

This species needs plenty of room to swim comfortably. This means you shouldn’t fill the tank with a ton of plants. Arrange plants sparingly around the back of the tank while leaving the middle portion relatively open.

The aquarium substrate should be covered in fine gravel. You can then bury and anchor plants into it. Stick with plants that have strong roots. Fine roots are much easier for your fish to dig up.

In addition to plants, you can utilize some driftwood or rocks. These accessories will serve as hiding spots for the fish whenever they are feeling a bit skittish.

Powerful filtration is a must with Silver Arowanas. They can be sensitive to noticeable quality changes.

A strong filter (we recommend the Fluval FX4) than can efficiently cycle the water and keep nitrate levels low is paramount. You should also replace 25 percent of the water weekly to keep ammonia and nitrates at acceptable levels.

Lastly, you need to do something to keep these fish in the tank.

One of the most important items you need for your Silver Arowana tank is a secure lid. These fish can reportedly jump up to 3 meters high in the wild!

They often try their luck in captivity, too. Oftentimes, the fish will stick to the surface of the water and look for opportunities to catch prey. So, you’ll need a weighted lid that you can secure onto the tank.

Author Note: If your Silver Arowana does manage to get out, try to get them back into the water as soon as possible. These fish can live out of the water for a bit by using their swim bladder, so don’t assume that they are dead if you see them on the floor outside of the tank!

Likelihood Of Disease

This fish species can suffer from a wide range of freshwater diseases. In addition to the common issues like Ich, Silver Arowanas are prone to experiencing a variety of fungal and parasitic infections. These include fin rot, Dropsy, and more.

Fin rot is caused by a bacteria that eats away at the fins. This results in a frayed appearance. In some cases, the condition can cause additional bacterial infections.

Dropsy is an infection of the lungs. It’s common in juvenile Silver Arowanas. The fish will swell up, causing the scales to protrude.

Another common issue you may have to deal with is physical injuries. Silver Arowanas are prone to damaging their barbels and suffering from abrasive injuries due to rubbing against sharp objects.

To deal with physical injuries, you’ll need to take a good look at the tank and remove anything that could cause harm. As for all of the other possible ailments, stress is the biggest factor.

Poor water conditions make fish more prone to bacterial and fungal infections. You can avoid a lot of potential health issues by simply maintaining the tank and keeping up with water quality.


Feeding Silver Arowanas is fairly straightforward. Theses fish are largely carnivores and while they can eat some plant-based foods, they need protein to truly thrive.

In the wild, you’ll see Silver Arowanas eating smaller fish, large insects, frogs, crustaceans, and more. They have even been known to eat rabbits and snakes!

In captivity, you can provide your fish with a healthy diet of frozen and live foods. They do well with feeder fish like minnows. Crab, crickets, and shrimp are good options, too.

You can provide earthworms, bloodworms, and any other protein-packed snack as well.

Some aquarists have seen success with dried pellets. However, this is rare. Silver Arowanas will need a nutritional diet of live and frozen foods to stay healthy. In our opinion, it’s not worth trying since it’s not enough for them regardless.

Behavior & Temperament

These fish are one of the most predatory in the aquarium trade. They will bully and eat any fish that can fit into their mouth, so you must exercise caution!

A feisty looking Silver Arowana up close

When they’re not searching for predators, Silver Arowanas can be surprisingly skittish.

They’re very aware of their surroundings at all times. If you suddenly walk up to a tank, they can get scared and quickly look for a hiding spot.

Over time, they will become more comfortable with you visiting the tank. But it’s still recommended that you keep the aquarium in a low-traffic area so that you don’t surprise the fish every time you walk by.

Silver Arowana Tank Mates

Finding suitable Silver Arowana tank mates is tough, plain and simple. They usually don’t do well with other Silver Arowanas unless you have a massive pond where they can stay out of each other’s way.

Pair that with their penchant for aggression and you have limited options when it comes to tank mates.

Generally, adding additional fish into the tank is hit-or-miss. All fish are different and you must keep a watchful eye on them to ensure that they get along.

If you want to create a small community, it’s best to go with fairly large fish that are slightly aggressive. That way, they can defend themselves against the Silver Arowana if an attack occurs. This will also mean they’re too big to be a viable meal!

Here are some possible tank mates to consider:

Author Note: It’s very important to note that with large aggressive fish like the Silver Arowana you need to approach this on a case by case basis. Some aquarists have had luck with tank mates on this list, and others haven’t. Pay close attention to the behavior of your fish and be prepared to separate them if needed.

The tank size you have available to you will impact the likelihood of these pairings succeeding as well. More space is always better!


Breeding Silver Arowanas in captivity is quite rare. Most of the fish you see in stores are from commercial fisheries.

This is because this species is quite finicky about breeding. They only do this during the flood season, which is around July. To make things even more difficult, it’s hard to get a bonded pair because the fish typically don’t get along with one another.

If you do have a bonded pair that chooses to breed, the process is interesting to watch. The female will lay her eggs after the two fish build a nest. Once all the eggs are laid, the male will scoop them up in his mouth.

Don’t worry! He’s not eating them. Silver Arowanas are mouthbrooders. The male will keep the eggs in his mouth for up to 50 days until they hatch. Then, the fry will stay for an additional 5 weeks.

At this point, the fish fry are pretty large. They can eat small feeder fish or brine shrimp without any issues.            

Are You Up For It?

By now you should have a pretty good idea of what it takes to keep one of these fish in a home aquarium. While Silver Arowana care isn’t the nightmare some fishkeepers make it out to be, it’s definitely not a walk in the park either.

If you have the space, time, and resources to help this species thrive then we highly encourage you to give it a shot. Owning a large and challenging freshwater fish is incredibly rewarding!

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