Often referred to as the Dragon Fish due to their shimmering, armor-like scales and majestic, undulating movements, the Arowana is the ultimate centerpiece for any serious freshwater aquarist. These prehistoric predators have patrolled the rivers of South America, Southeast Asia, and Australia for millions of years, and bringing one into your home is like keeping a living fossil. However, the Arowana is not a fish for the faint of heart or the small of tank; they are high-level commitments that require specialized care, massive amounts of space, and a deep understanding of water chemistry. For the intermediate hobbyist looking to make the leap into "monster fish" keeping, the Arowana offers a level of interaction and personality rarely seen in the aquatic world. They can learn to recognize their owners and even feed directly from your hand, but success hinges on your ability to provide a secure, clean, and appropriately sized habitat for these surface-dwelling titans.
Choosing Your Dragon: Common Arowana Species
In the aquarium hobby, there are three primary types of Arowana that hobbyists encounter, each with distinct sizes and temperaments. The most common entry point is the Silver Arowana (Osteoglossum bicirrhosum) from the Amazon Basin. These are beloved for their stunning metallic sheen and relatively docile nature toward large tank mates, but they are also the largest, often reaching lengths of three to four feet in captivity. Because they grow so quickly, many beginners make the mistake of buying a four-inch juvenile for a 55-gallon tank, only to find the fish has outgrown the space in less than six months.
The Australian Jardini Arowana (Scleropages jardinii) is another popular choice, known for its beautiful bronze coloration and intricate scale patterns. While they stay slightly smaller than the Silver variety—usually topping out around 24 to 30 inches—they are notoriously aggressive and highly territorial. A Jardini is often best kept as a solo specimen because they rarely tolerate other fish in their personal space. Finally, the Asian Arowana (Scleropages formosus) is the most sought-after and expensive, but due to CITES regulations, they are illegal to own in the United States. For North American hobbyists, focusing on the Silver or Jardini varieties is the practical path forward.
The Monster Tank: Space and Security Requirements
The single most important factor in keeping a healthy Arowana is the size of the aquarium. Because these fish have long, relatively inflexible spines, they require a tank that is wide enough for them to turn around comfortably without hitting the glass. For an adult Silver Arowana, a 250-gallon tank is often considered the bare minimum, with a footprint of at least six to eight feet in length and three feet in width. Keeping an Arowana in a narrow tank leads to "drop eye" and permanent spinal deformities that significantly shorten their lifespan. This is a significant jump from what are good freshwater fish for beginners, as it involves specialized floor reinforcement and industrial-grade equipment.
Security is the second pillar of Arowana housing. In the wild, Arowanas are famous for jumping several feet out of the water to snatch insects, birds, and even small monkeys from low-hanging branches. In a home aquarium, this instinct remains perfectly intact. A startled Arowana can hit the lid of a tank with enough force to shatter glass or displace a heavy plastic hood. You must have a heavy-duty, weighted, or locking lid to prevent your prized fish from ending up on the floor. Many professional keepers use weighted glass tops reinforced with heavy stones or specialized sliding tracks to ensure the "Dragon" stays in its den.
Water Quality and High-Performance Filtration
Arowanas are massive eaters, and consequently, they are massive waste producers. Their diet of high-protein foods leads to a rapid accumulation of organic compounds that can quickly turn a tank toxic. To manage this, you need a filtration system that is rated for at least double the volume of your tank. Sump filtration is generally preferred for Arowana tanks because it increases the total water volume and provides a massive surface area for beneficial bacteria. Maintaining pristine water is non-negotiable; even minor spikes in waste can lead to "Hole-in-the-Head" disease or fin rot. Understanding the dangers of high ammonia, nitrite and nitrate is vital, as a fish of this size and value has very little margin for error.
Consistency is more important than achieving "perfect" parameters. Silver Arowanas prefer slightly acidic to neutral water (pH 6.0–7.0) and temperatures between 75°F and 82°F. Because you will be performing large weekly water changes—often 30% to 50%—you must ensure the replacement water is properly dechlorinated and temperature-matched. Sudden shifts in temperature or pH during a water change can shock the fish's system, leading to a loss of appetite or a compromised immune system. Many intermediate keepers find that automating their water changes is the most reliable way to maintain the stability an Arowana needs to thrive over its 15-to-20-year lifespan.
Dietary Needs and Feeding Strategies
A healthy Arowana is a hungry Arowana. In captivity, you should aim for a varied diet that mimics their natural insectivorous and carnivorous habits. High-quality floating pellets should form the base of their nutrition, as these are formulated with the vitamins and minerals necessary for scale development and color. However, to keep an Arowana engaged, you should supplement with "meaty" treats. Frozen krill, silversides, crickets, and earthworms are excellent choices. Feeding live "feeder fish" is generally discouraged by experts, as these often carry parasites and diseases that can be passed to your Arowana, and they often lack the nutritional density of a prepared diet.
A common issue with Arowanas is "Drop Eye," a condition where one or both eyes begin to point permanently downward. While genetics and fatty deposits are often blamed, many keepers believe that feeding sinking foods encourages the fish to look down constantly, contributing to the condition. By using floating foods and ensuring the fish is always looking upward to feed, you can help maintain its natural aesthetic. Furthermore, avoid overfeeding; a juvenile can be fed daily, but an adult Arowana only needs a substantial meal every two to three days to prevent obesity and water quality degradation.
Provide a diet of 70% high-quality floating pellets and 30% fresh or frozen meaty foods.
Avoid feeder goldish to prevent the introduction of internal parasites and thiaminase issues.
Use long feeding tongs to prevent accidental bites, as Arowanas have sharp, backward-pointing teeth.
Feed in small amounts to ensure all food is consumed before it sinks and rots in the substrate.
Gut-load any insects like crickets or dubia roaches with high-quality vegetable matter before feeding them to your fish.
Compatibility and Tank Mate Considerations
Finding tank mates for an Arowana is an exercise in balancing size and temperament. The rule of thumb is simple: if a fish can fit in the Arowana's mouth, it eventually will. Therefore, tiny schooling fish like Tetras or Danios are strictly off the menu—or rather, they are the menu. You need companions that are large enough to be ignored but peaceful enough not to harass the Arowana's delicate trailing fins. Because Arowanas occupy the top layer of the tank, they pair exceptionally well with bottom-dwelling "monster" fish that stay out of their territory.
Ideal tank mates include large Freshwater Stingrays, provided you have a massive footprint and a sand substrate. Large Datnoids, Clown Knifefish, and robust Cichlids like Oscars or Severums can also work, though you must monitor for aggression. Avoid highly aggressive Cichlids like the Dovii or Umbee, as they may bully the Arowana, causing it to jump and injure itself. Compatibility is about more than just "not eating each other"; it's about shared water requirements and swimming space. This is a complex dynamic that builds upon the basics of freshwater fish compatibility, scaled up for giant species.
Select bottom-dwellers like Birchirs or large Plecos to occupy the lower water columns.
Ensure all tank mates are at least 50% of the Arowana's current body length.
Avoid nippy fish like Tiger Barbs that may target the Arowana's long, flowing anal and dorsal fins.
Monitor interactions closely during the first 48 hours after introducing any new tank mate.
Provide plenty of open swimming space; do not over-clutter the tank with large decorations that could scrape the Arowana's sides.
Common Pitfalls and Maintenance Tips
One of the most frequent mistakes intermediate keepers make is neglecting the "turning space" as the fish grows. An Arowana that cannot turn comfortably will become stressed and may stop eating. If you notice your fish swimming in a repetitive "pacing" motion or rubbing its nose against the glass, it is a clear signal that the tank size has been outgrown. Additionally, Arowanas are sensitive to "old water syndrome," where a lack of water changes leads to a slow drop in pH and a rise in nitrates. This can cause the fish's scales to lose their luster and its activity levels to plummet.
To keep your Dragon Fish in peak condition, use a soft sand or fine gravel substrate, or even a bare-bottom tank, to prevent detritus from becoming trapped. Regularly check your heater to ensure it is guarded; a large Arowana can accidentally break a glass heater or burn itself if it rests too close to the heating element. Finally, always have a "Plan B" for power outages. Because Arowanas are so large, they consume oxygen rapidly. A battery-powered aerator can be a literal lifesaver during a storm, keeping the water oxygenated until the main filtration can be restored.
Perform 40% weekly water changes to keep nitrates below 20ppm.
Check the lid weights or locks every evening before the lights go out.
Rinse filter media in tank water monthly to prevent clogging from heavy waste.
Use a turkey baster to remove uneaten food immediately after feeding sessions.
Install a secondary air stone to ensure maximum oxygenation in the upper water levels.
Takeaway: The Reward of Keeping a Living Legend
Keeping an Arowana is a journey that moves a hobbyist into the realm of true aquatic specialists. It requires a significant investment of time, money, and space, but the reward is a pet that offers unparalleled grace, beauty, and intelligence. By selecting a species that fits your experience level, providing a massive and secure environment, and committed to a rigorous maintenance schedule, you can successfully host one of nature's most impressive predators. The Arowana is more than just a fish; it is a statement piece and a long-term companion that will grow with you over the decades. If you are ready to take the leap into the world of monster fish, start by securing the largest tank possible and mastering your filtration. Do you have questions about specific filtration setups or advanced Arowana health? Explore our library of expert articles at RateMyFishTank.com to ensure your Dragon Fish thrives for years to come!
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