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Jardini arowanas are large and intimidating freshwater fish that aren’t suitable for many aquarists. But if you have the necessary experience (and room), then owning one can be incredibly rewarding.

Read this guide to learn about the care guidelines for this species. We’ll cover their size, lifespan, ideal tank size, feeding requirements, and more!

Species Summary

The jardini arowana (Scleropages jardinii) is a unique freshwater fish species with many different names. It’s sometimes referred to as the Australian arowana. In other circles, they call it the water monkey!

Whatever you call it, there’s no denying that this fish is quite interesting. It’s native to bodies of water in Australia and New Guinea. They typically inhabit flooded plains, slow-moving streams, and swamps.

In captivity, these fish can be a real challenge for hobbyists. Not only does their sheer size make them difficult to keep, but their predatory nature can be a nightmare without proper planning.

Many consider the jardini arowana care to only be attainable by seasoned fish-keepers. Even then, plenty of research and a deep understanding of the fish’s needs is a must.

Appearance

Arowana fish have a distinct appearance that’s easy to identify, and the jardini is no exception.

The fish’s body is long and slender. Both the dorsal and anal fins sit far back on the body, ending just before the tail. The fins are all rayed, but they’re comparatively small, considering the fish’s length. As a result, many mistake them for small eels!

The head and mouth are among the most defining features of the arowana. The species has big, beady eyes and a pointed face. The mouth is upturned, and the fish can open it into a gaping maw to hunt its prey.

On the tip of the mouth are a few barbs. The whisker-like appendages are subtle but play an important role in the fish’s hunting habits. That’s not all.

Inside the jaw, jardini arowana has a line of spiky teeth! They’re perfect for munching prey, but they can present a safety risk if your fish mistakes your finger for food!

Author Note: Sexual dimorphism is subtle. Males and females are nearly identical, but the males usually have longer anal fins, lower-set pectoral fins, and lengthier whiskers.

The color is relatively muted on most jardini arowanas. The standard is silver-gray or slightly beige. However, the scales do create a beautiful shimmer in the right light. You may encounter fish with black or brassy coloration. Rare coral-colored fish exist, too.

Lifespan

There’s no way to guarantee how long a fish will live. Like any other species, jardini arowana can succumb to illness and premature death. They’re one of the more sensitive freshwater fish, so high-quality care is paramount.

In the right living conditions, the average jardini arowana lifespan is between 10 and 20 years.

Author Note: It’s worth pointing out that this is only in captivity. In the wild, this species is known to live as long as 50 years!

Average Jardini Arowana Size

One of the biggest challenges you’ll face raising jardini arowana fish is their massive size. They may only be a few inches long when you first buy them from a breeder or fish store as juveniles, but this species grows fast.

With the right diet, the arowana can grow about two inches per month. By the time they’re a year and a half old, they reach their full size. So how big do these fish get?

The average size of a jardini arowana in captivity is 24 inches! In the wild, this fish is capable of growing to reach 36 inches in length.

Care

A fish as big and aggressive as the jardini arowana can be a handful. This species is not for the faint of heart or the inexperienced, but don’t let its difficulty deter you from taking up the challenge if you’re prepared (be honest with yourself about this).

Jardini arowana can be a joy to take care of, and they often become the centerpiece of a hobbyist’s collection. Their beauty and unique behavior always draw attention.

To ensure that your fish live long, happy, and healthy lives, stick to the care guidelines below.

Jardini Arowana Tank Size

If you want to keep jardini arowana, be prepared to invest in a massive tank! With average sizes reaching 24 inches, a small or even moderately sized aquarium won’t cut it. 

You need a tank size of at least 180 gallons to keep these fish healthy. If possible, bump that volume up to 200 gallons or more. Anything smaller than 180 gallons will not work with the fish’s lifestyle.

It’s not uncommon to see these fish living in large backyard ponds. If you live in an area with a good climate, 500-plus-gallon ponds could be the best solution for this species.

Technically, you can go smaller during the juvenile phase. Many hobbyists start with an aquarium as small as 75 gallons as they raise juveniles. But given the fish’s fast growth rate, it’s only a matter of time before upgrades are necessary.

180-gallon aquariums are enough for a single jardini arowana and possibly some bottom-dwelling fish. 

Author Note: When choosing a habitat, focus on length over height. This species likes to stay close to the surface of the water, but it swims back and forth and needs plenty of room to turn around.

Water Parameters

The natural environment of the jardini arowana is unique. They come from relatively shallow streams and marshes. Sometimes, they even reside in swamps.

Those bodies of water are typically on the acidic side and have a small amount of acidity. When setting up your tank, the best thing you can do is create similar living conditions.

Give your tank time to cycle for up to eight weeks before introducing your fish. Jardini arowanas are sensitive to parameter changes, so they need a well-established tank to thrive. It’s also important to monitor conditions continually.

Stability is key, so regular water checks and frequent partial water changes are necessary. Here are core water parameters to follow when setting up your tank.

• Water temperature: 75 to 86 degrees Fahrenheit (Around 82 degrees is the sweet spot)
• pH levels: 6.0 to 7.5 (Slight acidity)
• Water hardness: up to 16 DH

Tank Setup

The jardini arowana likes things comparatively simple when it comes to decor and their tank setup. The over-the-top freshwater tanks that South American and African species prefer are simply too much for this fish.

You must remember the natural environment where this species comes from. It’s native to shallow marshes, streams, and sometimes swamps. They stick to the top of the water column and rarely venture below.

Because of this, simplicity is best.

Start with a layer of sand or rock substrate. The jardini isn’t picky about the substrate, but sand or rocks can create a more natural feel. 

Add a large piece of driftwood, and you’re good to go. The substrate will serve as a water-enricher, helping maintain acidity levels as it deteriorates and releases tannins. It’ll also support plant life.

Jardini arowana love richly planted tanks. You can get creative with vegetation, but to support the fish’s lifestyle, make sure to add plenty of floating plants.

They’ll eventually anchor to the driftwood to cement the habitat. Don’t overdo it with plants. A lot of vegetation is good, but the jardini arowana still needs open swimming space.

For equipment, invest in a powerful filter. These large fish produce significant waste, and you need a sound filtration system to handle it all. Use the pump of your filter to create a moderate current.

Jardini arowana fish appreciate oxygenation and will frequently swim against the current like they do in the wild.

Author Note: Remember to top everything off with a secure tank. This fish gets its “water monkey” nickname for its habit of leaping out of the water to catch prey. They will attempt to do this in captivity, so a tight lid is a must if you don’t want to find your fish on the floor!

Common Possible Diseases

Despite its formidable nature, the jardini arowana is not immune to disease. It’s a sensitive fish that won’t tolerate substantial environmental changes. Excellent care with regular monitoring, frequent water changes, and a solid filtration system are necessary to keep these fish healthy.

When conditions sour, this fish will suffer from a wide range of illnesses. They can experience all the usual freshwater ailments such as Ich. However, some of the most common problems are:

• Gill rot
• Swim bladder disease
• Drop eye

Gill rot is a product of lackluster water conditions. Fungal spores develop in the water and flow into the arowana’s gills. The result is potentially lethal infection.

You can avoid gill rot by maintaining the tank well and performing frequent water changes to keep ammonia levels under control.

Swim bladder disease is usually a result of dietary issues. Over-feeding can cause constipation issues. When that happens, the organ that influences buoyancy goes out of whack, creating swimming difficulties for the fish.

Finally, we have a condition known as drop eye. This unique condition only affects fish with a penchant for fast swimming and jumping. When a jardini arowana attempts to leap out of a closed tank, they will hit their heads, causing the eyes to drop.

If this happens, the best thing you can do is cover the sides of the tank. That forces the fish to look up constantly. It can correct the drop eye and make the fish more aware of the obstacle above them.

Food & Diet

Jardini arowanas are carnivores through and through! They are predators and often go to great lengths to catch prey in the wild. To keep your fish healthy, you must provide a similar diet in captivity.

You can provide a healthy mix of high-protein foods. The fish prefer live insects like earthworms, bloodworms, and crickets. Most of those items are easily sourced at pet stores.

Some aquarists will also provide live frogs, minnows, and shrimp. Many stores sell live feeder goldfish but resist the urge to give those fish as meals. They can introduce parasites and bacteria into your tank, causing more trouble than they’re worth.

Plenty of other high-protein foods are available, so there’s no need to resort to potentially disease-ridden feeder fish.

It’s also a good idea to provide vitamins. Vitamin-enriched foods are available as sticks, pellets, and frozen cubes. Get your fish used to eating non-live fish early, and they’ll have no problem eating vitamin supplements.

Author Note: Juveniles need to eat twice a day and get as much food as they can in two minutes. Stick to that two-minute rule. It’ll help you avoid over-feeding and save you from cleaning up leftovers before they decay.

As your arowana grows, slowly transition to one meal a day.

Behavior & Temperament

Jardini arowana can be temperamental creatures. They’re predators with naturally aggressive tendencies! It’s in their nature, so it’s something you should always plan for.

It’s possible to keep jardini arowana with other fish (more on that in a second). However, they’re perfectly content living by themselves. In either situation, the fish usually spends its days grazing the surface.

They do this to look for food. Even if your tank is covered, their instincts force them to be on the lookout for whatever flies above the water. As mentioned earlier, they can leap out of the water to catch insects and other prey animals.

This species rarely ventures to the bottom of the tank, but it will explore the available swimming space.

Tank Mates

You wouldn’t think an aggressive fish like the jardini arowana could have tank mates, but they can. It all comes down to your fish’s tendencies. Some are more aggressive than others, and you must use your best judgment to determine if tank mates are possible.

The best tank mates are similarly sized fish that the jardini arowana can’t eat. If you have a large enough tank, you could try the following:

Always keep an eye on your arowana. A large tank and plenty of decor for the other fish to hide will help keep the aggression at bay, but there are no guarantees with this species.

Breeding

Breeding jardini arowana in captivity is possible, but it’s not easy. First, you need a massive breeding tank. A pair of breeding jardini arowanas need a habitat of at least 600 gallons. Because of this, most breeders use an outdoor pond.

Place a bonded pair into the pond that’s not all the way filled. As you prepare them for spawning, provide premium high-protein foods and slowly fill the pond to the top. The filling process replicates the conditions of the wet season, the time when these fish breed naturally in the wild.

Jardini arowanas are mouthbrooders. Females lay up to 200 eggs. Then the male fertilizes them and scoops them in his mouth for incubation. They stay in the mouth for about two months before hatching.

You don’t have to worry about removing the parents after the eggs hatch. They are both fiercely protective of the fry, and they will continue looking after them for another month or so. Even after that, the mother will open her mouth when danger is present, allowing the young fish to hide in her mouth!

Wrapping Up

For many, owning a jardini arowana is not realistic. These fish require an extensive amount of experience and sufficient space in order to thrive.

But if you’re an aquarist who’s capable of caring for this species, give it a shot! These unique fish can be quite rewarding to own.