SILVER AROWANAS (SMALL)

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!

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.

Lifespan

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.

Appearance

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.

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.

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.

Size

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.
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.

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

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.

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.

Feeding

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!

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:

• Large catfish
• Parrotfish
• Jaguar Cichlid
• Pacu (if the tank is large enough)
• Silver Dollar Fish
• Large Plecos
• Bichir
• Green Terror Cichlid
• Black Ghost Knife Fish

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

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.