Asian Arowana – Scleropages formosus

The Asian Arowana, Scleropages formosus, is one of the most admired and controversial aquarium fish in the world. Graceful, powerful and steeped in cultural symbolism, it fascinates aquarists who dream of keeping a “dragon fish” in their living room. At the same time, it is demanding, sensitive and subject to strict legal rules. This guide introduces the species, its needs and the key elements of responsible care, with practical tips for aquarists planning a suitable aquarium and equipment, such as those available at MB Store.

Natural habitat and biology of the Asian Arowana

Asian Arowanas occur naturally in slow-moving, warm freshwater rivers, swamps and blackwater habitats of Southeast Asia, including Indonesia, Malaysia, Thailand, Cambodia and parts of Vietnam and Myanmar. These waters are often shaded by dense vegetation, rich in fallen leaves, branches and roots. The resulting tannin-stained water is slightly acidic to neutral and relatively soft, with low visibility and gentle water movement.

In nature, Scleropages formosus is a surface-dwelling predator. Its long, torpedo-shaped body and upturned mouth are perfectly adapted for hunting insects, small fish and crustaceans just below the water surface. The fish is an adept jumper, capable of leaping to catch prey from overhanging branches. This natural behaviour becomes critical in aquarium planning because Arowanas can and will jump from open tanks.

Asian Arowanas can reach 60–90 cm in length, although captive specimens often remain slightly smaller, depending on space, diet and genetics. They are slow-growing compared to many aquarium fish and can live 15–20 years or more in optimal conditions. Such a lifespan makes them a long-term commitment, similar to a large parrot or dog.

Sexual dimorphism is subtle. Males usually have a more slender body and longer anal and dorsal fins, while females are often deeper-bodied. Breeding in captivity is a complex topic and usually undertaken only by experienced keepers with very large aquariums or ponds, because the species is a mouthbrooder: the male carries eggs and fry in his mouth for several weeks.

Varieties, coloration and cultural significance

One of the biggest attractions of the Asian Arowana is the variety of colour morphs selectively bred over decades. Different forms are associated with specific regions and genetic lines. Among the best-known varieties are:

• Red Arowana (commonly called Super Red, Blood Red): originating mainly from West Kalimantan, Indonesia. Young fish may be orange or pale, with intense red coloration developing as they mature. Fins, gill covers and scales can range from orange-red to deep crimson.
• Golden Arowana (Crossback Golden, 24K Golden): particularly valued for its shining metallic scales that can “cross back” over the top of the body. Colouration may range from pale gold to a rich, saturated yellow-gold that covers all rows of scales.
• Green Arowana: widely distributed and usually more modestly coloured, with greenish, olive or bronze hues and less intense shine. Often considered one of the more robust varieties, suitable for keepers who value natural colours over extreme brightness.
• Blue-based and purple-based Arowanas: lines selectively bred for cool-toned sheens on scales and fins. In the right light, they display iridescent blue, violet or platinum reflections.
• Banjar Red and Yellow Tail forms: sometimes grouped together with reds, but genetically and visually distinct. They often retain orange, yellow or copper tones, without achieving the deep crimson of true Super Reds.

Beyond their beauty, Asian Arowanas carry deep cultural significance in many Asian countries. Often called “Dragon Fish” due to their long body, shiny scales and barbels resembling whiskers, they are associated with strength, prosperity and good fortune in feng shui. In some communities, owning a large, healthy Arowana is considered a status symbol, representing success in business and life.

This cultural value has driven demand, contributing to overfishing and illegal trade in the past. Today, most legally sold Asian Arowanas come from licensed farms and are registered under CITES (the Convention on International Trade in Endangered Species). Each legal specimen is microchipped and accompanied by certificates that identify its origin, variety and registration number. Responsible aquarists should insist on this documentation.

Legal aspects and ethical considerations

Scleropages formosus is listed in CITES Appendix I, which covers species threatened with extinction and subject to strict trade controls. This means the international trade of wild-caught specimens is prohibited, and commercial trade is only allowed for captive-bred fish from approved facilities. Laws differ from country to country: in some places, Asian Arowanas are completely banned, while in others they can be kept only with specific permits.

Before acquiring an Asian Arowana, prospective owners must:

• Check national and local regulations regarding possession and trade.
• Buy exclusively from reputable dealers who can provide valid CITES paperwork and microchip data.
• Verify that the fish is farm-bred and registered; illegal specimens may be confiscated, and owners can face legal consequences.

Ethically, aquarists should also consider whether they can provide long-term suitable conditions for such a large, demanding predator. The romantic image of a dragon fish can overshadow the reality of tank size, filtration, diet, and behavioural needs. Keeping an Arowana in a small tank “until it grows” is both unhealthy and misleading: growth may be stunted, leading to deformities and stress-related illnesses.

From a conservation standpoint, supporting legitimate, well-regulated farms helps reduce pressure on wild populations. Illegal trade, however, threatens natural stocks and undermines conservation programs. Responsible hobbyists, retailers and manufacturers all share a role in promoting correct information and ethical standards.

Aquarium size, layout and essential equipment

Providing a suitable home for an Asian Arowana is the cornerstone of successful care. This is not a fish for standard-sized aquariums. An adult specimen demands substantial space, strong filtration and carefully planned tank geometry.

Recommended tank size

For a single adult Asian Arowana, the absolute minimum aquarium size is usually considered around 180–220 cm in length, 70–80 cm in width and 60–70 cm in height. Larger is always better, especially in width, as Arowanas need ample turning space to avoid body and fin injuries. Juvenile fish may start in smaller tanks, but planning for the final adult tank from the beginning is far wiser.

Long, wide tanks are preferred over tall, narrow ones. Since Arowanas swim mainly at the surface, horizontal swimming room matters more than overall water depth. Front-to-back width reduces stress and makes turning easy, lowering the risk of abrasions, jaw injuries and damaged scales.

Tank layout and decor

The ideal Arowana setup is relatively minimalist, with a focus on open swimming space and safe surfaces:

• Choose fine sand or smooth gravel as substrate to avoid injuries if the fish dives in panic.
• Use sturdy driftwood and large roots carefully positioned along the back or corners, leaving the central area open.
• Select plants that can tolerate limited disturbances or use potted plants along the edges. Floating plants provide shade and a sense of security but should not completely cover the surface.
• Avoid sharp rocks and decorations with narrow gaps in which the fish could get stuck.

Secure covers are absolutely essential. Asian Arowanas are powerful jumpers and can escape even through small openings around filter hoses or cables. A tight-fitting lid or cover glass, supported by a sturdy frame, is mandatory. Consider adding weight or locks to prevent accidental lifting.

Filtration and water movement

Arowanas are large, messy predators. Their diet of meaty foods produces significant organic waste. Consequently, mechanical and biological filtration must be efficient and reliable. Oversized external canister filters, sump systems or combinations of both are common solutions in Arowana tanks.

The filtration system should ensure:

• Excellent removal of particulate matter (uneaten food, feces).
• Strong biological capacity to handle ammonia and nitrite spikes.
• Gentle to moderate water movement that avoids strong surface turbulence.

Many keepers prefer sump systems, which allow custom media configurations, additional water volume and easy maintenance. External canister filters from reputable brands, when properly sized, also perform very well. MB Store offers a selection of high-quality filters, pump systems and media suitable for large predatory fish, enabling aquarists to build a reliable filtration system tailored to their tank.

Lighting and covers

Asian Arowanas look spectacular under appropriate lighting, which enhances their metallic sheen and body colour. Adjustable LED lighting is a popular choice, offering customizable intensity and spectrum. However, lighting should not be excessively bright, as too much intensity can stress the fish and encourage jumping behaviour.

Many aquarists aim for moderate, diffuse light with some shaded areas created by floating plants or decor. Some specialised Arowana keepers use particular light spectrums to highlight red or gold tones, but the fish’s comfort and health should always come first.

MB Store provides a wide range of aquarium lighting solutions, including modern LED systems with adjustable colour and brightness, as well as high-quality glass covers and tank frames that help prevent escapes while showcasing the fish.

Water parameters and maintenance routine

Stable and high-quality water conditions are essential for an Asian Arowana’s long-term health. While the species can tolerate a certain range of parameters, consistency is more important than chasing exact numbers.

Recommended parameters

• Temperature: 26–30 °C. A commonly targeted range is 27–28 °C.
• pH: 6.0–7.5. Slightly acidic to neutral is ideal.
• General hardness (GH): soft to moderately hard, depending on local water.
• Ammonia and nitrite: 0 mg/L at all times.
• Nitrate: preferably below 20–40 mg/L, achieved through water changes and good filtration.

Heaters must be reliable and adequately powerful for the tank’s volume. Many keepers use two slightly underpowered heaters instead of one strong heater. This configuration reduces the impact of a single heater malfunction and helps maintain a more even temperature.

Water change schedule

Due to the high bioload of a large Arowana, regular water changes are non-negotiable. A typical schedule is 25–40% of the volume once per week, although some keepers prefer smaller, more frequent changes. The exact frequency depends on tank size, filtration efficiency, stocking level and feeding intensity.

When performing water changes:

• Match temperature and pH as closely as possible to avoid sudden shocks.
• Use a suitable water conditioner to neutralize chlorine and chloramines.
• Vacuum the substrate where debris accumulates, especially in less active areas.

Testing water parameters regularly is a must, especially in the first months after setting up the system. Quality test kits for ammonia, nitrite, nitrate and pH, together with thermometers and possibly TDS meters, allow early detection of problems and fine adjustments in maintenance schedules.

Aquarium cycling and introduction of the fish

An Arowana should never be introduced into an uncycled aquarium. The biofiltration system must be fully established and capable of processing waste. A fishless cycle using ammonia or bacterial starters is strongly recommended. Only when ammonia and nitrite remain consistently at zero after test doses should such a valuable and sensitive fish be added.

When introducing a new Arowana, slow acclimatization helps reduce stress. Many aquarists use drip acclimation, gradually mixing aquarium water into the transport bag over 30–60 minutes. Care must be taken to avoid temperature swings, and the tank lights should be dimmed during the process.

Feeding and nutrition for optimal health and colour

As a carnivorous predator, Scleropages formosus requires a protein-rich diet with appropriate fats, vitamins and minerals. At the same time, feeding must be controlled to avoid obesity, fatty liver disease and poor water quality.

Juvenile Arowanas

Young Asian Arowanas grow rapidly and need frequent, smaller feedings. Suitable foods include:

• High-quality floating carnivore pellets formulated for large predators.
• Frozen or live foods such as bloodworms, small shrimp, chopped fish and insect larvae.
• Occasional live insects like crickets or mealworms, always from clean sources.

Two to three feedings per day in small portions are appropriate for juveniles. It is beneficial to train young Arowanas to accept pellets early, as this simplifies adult feeding and ensures balanced nutrition with added vitamins and trace elements.

Adult Arowanas

Adult specimens require less frequent but substantial meals. Overfeeding is a common mistake: their eager feeding behaviour can mislead owners into giving too much. Recommended staples for adults include:

• Large floating pellets for carnivorous fish, containing quality marine and freshwater proteins.
• Frozen shrimp, krill, fish fillets and similar items, thoroughly thawed before use.
• Occasional live prey (if local regulations and ethics permit), such as feeder fish raised in quarantine systems, though many keepers avoid feeders due to disease risk.

Feeding once per day, or even every other day for mature individuals, is often sufficient. The amount should be such that all food is consumed within a few minutes without leftovers sinking unnoticed. Uneaten food quickly pollutes the water, particularly in warm temperatures.

Foods to avoid and supplements

Some food items are best avoided or kept as rare treats:

• Mammalian meat (beef heart, chicken) can cause long-term health issues due to incompatible fats.
• Fatty fish and processed meats trigger obesity and degrade water quality.
• Wild-caught insects may contain pesticides or parasites.

Balanced commercial pellets already contain vital vitamins and minerals. However, some keepers use additional vitamin supplements, soaking frozen foods or pellets before feeding. This can support immune function and intensify colour, but care is required not to overdose.

Colour development, particularly in red and golden varieties, is influenced by genetics, overall health, stress levels, water quality and diet. Carotenoid-rich foods (such as krill and certain crustaceans) may help, but they cannot transform a fish beyond its genetic potential. Responsible aquarists prioritize health over extreme colour enhancement.

Tankmates and behaviour

The Asian Arowana is typically kept as a centerpiece fish. Its size, predatory instincts and territorial nature make community aquariums challenging. Nonetheless, with careful planning and a sufficiently large tank, certain combinations can work.

General behaviour

Arowanas are surface-oriented and patrol the upper layer of the tank. They are curious, intelligent and quickly recognize their caretaker, particularly at feeding time. However, they can also be skittish, especially in new environments or under sudden lighting changes. Rapid movements near the tank or loud sounds may trigger panic, resulting in violent jumping or collisions with the lid.

Intraspecific aggression – aggression toward other Arowanas – is common in confined spaces. While groups are sometimes maintained in very large ponds or custom-built tanks, smaller aquariums usually only allow safe housing of a single specimen.

Suitable tankmates

Potential companions must be:

• Large enough not to be viewed as prey.
• Robust and confident, yet not overly aggressive.
• Occupying different levels of the tank (midwater, bottom).

Examples often considered include some larger catfish (such as certain species of Plecostomus and peaceful pimelodids), big barbs or robust cichlids, and large bichirs. Each combination should be researched in detail, taking into account adult size, temperament and water parameter compatibility.

Small fish, shrimps and most snails will sooner or later become food. Delicate species, fin-nippers and hyperactive fish should also be avoided, as they either stress the Arowana or get injured.

Managing aggression and stress

Signs of stress in an Arowana include faded colour, clamped fins, frantic swimming, rubbing against objects and loss of appetite. Causes might be poor water quality, insufficient space, inappropriate tankmates, or sudden changes in the environment.

Strategies to reduce stress include maintaining consistent lighting cycles, providing subdued illumination periods at dawn and dusk, avoiding moving objects quickly near the aquarium and ensuring strong water quality management. When introducing new tankmates, careful observation is crucial. Aggressive or bullying fish should be rehomed quickly to avoid long-term issues.

Health, diseases and long-term care

With excellent husbandry, Asian Arowanas can remain healthy for many years. However, several health problems are relatively common in this species. Preventive care is far more effective than treatment after the fact.

Common ailments

• Parasitic infections: External parasites like ich (white spot), flukes or protozoans can occur, especially after stress or new introductions without quarantine. Symptoms include white dots, mucus, flashing and respiratory distress.
• Bacterial infections: Fin rot, ulcers and systemic infections often result from injuries, poor water quality or chronic stress. Early treatment and improved conditions are vital.
• Swim bladder problems: Buoyancy issues may arise from physical trauma (jumping into the lid) or internal disorders. The fish may float at the surface, sink uncontrollably or tilt during swimming.
• Eye problems: Cloudy eyes, swelling or the so-called “drop eye” (eye pointing downward) have been reported. Causes may include genetics, diet, fatty degenerations, frequent bottom-gazing due to reflective tank bases or long-term water quality issues.
• Jaw and barbel injuries: As active jumpers, Arowanas often injure themselves against lids or decor. Deformed jaws and broken barbels can interfere with feeding.

Prevention through husbandry

The foundation of disease prevention is optimal, stable water quality and appropriate nutrition. Avoid adding new fish, plants or decor without proper cleaning and quarantine. Observing the Arowana daily enables early detection of subtle changes in behaviour or appearance.

Quarantine tanks can be extremely useful for treating diseases without exposing the main system to medications. Many treatments affect filtration bacteria, plants or invertebrates, so reading labels carefully and monitoring ammonia and nitrite during medication courses is critical.

Consulting aquatic veterinarians or experienced keepers is helpful when dealing with serious or unfamiliar conditions. Successful treatment often requires precise identification of the problem, as different diseases can present similar symptoms.

Long-term commitment and growth management

Owning an Asian Arowana is a multi-year project. Proper planning should include:

• Considering the adult size and upgrading the tank before the fish outgrows its initial home.
• Ensuring access to high-quality food and supplements long term.
• Budgeting for electricity, water changes, filter media and potential repairs.
• Finding trustworthy pet sitters or family members capable of basic care during holidays.

Stunted growth due to undersized tanks or chronic malnutrition not only diminishes the fish’s beauty but also impairs its organ development and life expectancy. A healthy, well-grown Arowana exhibits powerful, coordinated swimming, full fins, bright eyes and vibrant, even colouration.

MB Store supports aquarists in meeting these demanding requirements by offering high-quality aquariums, stands, filtration systems, heaters, lighting and accessories suitable for large predatory fish. With proper equipment and knowledge, the dream of keeping an Asian Arowana can become a sustainable reality.

Asian Arowana and the broader aquarium hobby

While Scleropages formosus is a specialty fish suited only to experienced keepers, its presence in the hobby influences aquarium culture more widely. The attention paid to water quality, filtration, tank design and ethical sourcing in Arowana keeping sets a high bar that benefits other species as well.

Many aquarists who begin with community tanks and smaller fish eventually aspire to keep an Arowana. This progression often leads to deeper interest in biology, engineering and environmental issues. Building or purchasing a large, custom tank requires understanding structural support, glass thickness, pump capacities and energy consumption. In this way, the “dragon fish” acts as a bridge between casual fishkeeping and advanced aquatic husbandry.

Retailers and manufacturers also respond to this demand by innovating in tank construction, overflow systems, lighting and automation. MB Store, for instance, aims to provide not only products but also guidance, helping customers select aquarium sizes, filters and accessories proportionate to the species they plan to keep. For those not yet ready for a massive predator, the same principles – stable water conditions, appropriate stocking, thoughtful layout – apply equally to community aquariums and planted tanks.

Ultimately, the Asian Arowana represents more than just a beautiful fish. It symbolizes the responsibility that comes with keeping complex, long-lived animals in artificial environments. By learning from the needs of this demanding species, aquarists can improve their practices across all their aquariums, fostering healthier, more naturalistic and ethically grounded fishkeeping.

FAQ – Asian Arowana (Scleropages formosus)

Is the Asian Arowana suitable for beginners?
No. Asian Arowanas are large, demanding and long-lived predators. They need huge tanks, powerful filtration, stable water parameters and careful handling. Their legal status also complicates purchase and ownership. Beginners should start with smaller, hardier species before attempting an Arowana.

What is the minimum tank size for an Asian Arowana?
For an adult, a tank at least 180–220 cm long and 70–80 cm wide is recommended, with generous swimming space and strong filtration. Larger dimensions are always better. Small tanks quickly cause stress, deformities and stunted growth, so planning for the final adult size is essential before purchase.

Can I keep other fish with my Asian Arowana?
Possible, but only with great care. Tankmates must be large enough not to be eaten, robust but not overly aggressive, and compatible with similar water conditions. Even then, conflicts can occur. Many keepers opt for a single Arowana with a few large, peaceful bottom dwellers, watching behaviour closely.

How expensive is it to keep an Asian Arowana?
Costs include a large, sturdy aquarium, strong filtration, heaters, lighting and quality food. Electricity, water changes and replacement media add ongoing expenses. Some colour varieties are very expensive to buy. Overall, keeping an Arowana is significantly more costly than maintaining a typical community tank.

Do Asian Arowanas recognize their owners?
Many keepers report that Arowanas quickly associate their owner with feeding and approach the front glass when someone familiar appears. While we should be cautious with interpreting behaviour, they clearly learn routines and respond to movements and presence, showing a level of awareness uncommon in smaller fish.