How Long Do Arowana Fish Get – Your Ultimate Growth & Care Guide

Written ByHoward Parker

Hey there, fellow aquarist! Have you ever found yourself mesmerized by the sheer majesty of an arowana, dreaming of adding one of these living jewels to your home aquarium? You’re not alone. These magnificent fish are truly captivating, with their ancient lineage and distinctive, powerful presence. But before you dive in, there’s one crucial question that every aspiring arowana keeper needs to ask: how long do arowana fish get?

It’s a common query, and for good reason! Understanding the potential size of these impressive predators is absolutely fundamental to their well-being and your success as a keeper. Many enthusiasts underestimate just how large a healthy arowana can become, leading to challenges down the road. But don’t worry—you’re in the right place!

This comprehensive guide will demystify everything about arowana growth. We’ll promise to arm you with expert insights, practical tips, and a clear understanding of what it takes to raise a thriving, full-sized arowana. By the end, you’ll know not only the answer to “how long do arowana fish get,” but also how to ensure your arowana reaches its full, healthy potential, avoiding common pitfalls and embracing the best practices for these incredible creatures.

Let’s dive in and unlock the secrets to arowana growth, care, and a truly majestic aquarium experience!

Understanding Arowana Growth: So, how long do arowana fish get, really?

When it comes to arowanas, size isn’t just a number; it’s a testament to proper care and a suitable environment. The answer to “how long do arowana fish get” largely depends on the specific species, but one thing is consistent: they get big. Much bigger than many new aquarists anticipate!

Let’s break down the typical adult sizes for some of the most popular arowana species:

  • Silver Arowana (Osteoglossum bicirrhosum): This is perhaps the most common species found in the hobby, and they are also the largest. A healthy Silver Arowana can easily reach lengths of 3 to 4 feet (90-120 cm) in a suitably sized aquarium or pond. In the wild, they can grow even larger.
  • Asian Arowana (Scleropages formosus): Revered for their vibrant colors and cultural significance, Asian Arowanas (including varieties like Red, Gold, Green, and Chili Red) typically grow to about 2 to 3 feet (60-90 cm). While slightly smaller than Silvers, they are still incredibly robust fish.
  • Jardini Arowana (Scleropages jardinii): Also known as Australian Arowana or Pearl Arowana, these fish usually mature at around 2 to 2.5 feet (60-75 cm). They have a more stocky build compared to the slender Silver Arowana.
  • Black Arowana (Osteoglossum ferreirai): Closely related to the Silver Arowana, Black Arowanas are known for their striking dark coloration as juveniles. As adults, they lighten somewhat but still reach impressive sizes, generally 2.5 to 3 feet (75-90 cm).

It’s important to understand that these are adult lengths. Arowanas grow quite rapidly, especially in their first year, often adding an inch or two (2.5-5 cm) per month. This quick growth spurt means that a small juvenile arowana will very quickly outgrow a starter tank.

Key Factors Influencing Arowana Growth & Size

Knowing how long do arowana fish get is just the first step. The real art lies in understanding the environmental and care factors that allow them to reach their genetic potential. Think of it like raising a child; genetics play a role, but nutrition, environment, and care are paramount. Here are the crucial elements:

Tank Size: The Non-Negotiable Foundation

This is, without a doubt, the most critical factor. An undersized tank is the primary cause of stunted growth and health issues in arowanas. These fish are active, powerful swimmers that need ample space to turn, hunt, and simply exist comfortably.

  • For a single Silver Arowana, a minimum tank size of 300 gallons (1135 liters) is often recommended, with dimensions of at least 8 feet long x 3 feet wide x 2.5 feet tall (240cm x 90cm x 75cm). Larger is always better.
  • For Asian, Jardini, or Black Arowanas, a minimum of 180-250 gallons (680-945 liters) with dimensions of at least 6-8 feet long x 2.5-3 feet wide x 2 feet tall (180-240cm x 75-90cm x 60cm) is generally advised.

When an arowana is kept in a tank that’s too small, its growth can become stunted. While the fish might appear to stop growing externally, its internal organs continue to try and develop, leading to severe health problems, deformities, and a significantly shortened lifespan. This isn’t a “bonsai” effect; it’s detrimental.

Diet & Nutrition: Fueling Robust Growth

To reach their impressive adult size, arowanas need a high-quality, varied, and protein-rich diet. They are opportunistic predators, and their diet should reflect this.

  • Staple Diet: High-quality arowana pellets or sticks should form the base, ensuring they receive essential vitamins and minerals.
  • Frozen Foods: Offer a variety of frozen options like krill, silversides, shrimp, and bloodworms (for juveniles).
  • Live Foods (with caution): While live feeder fish can be offered, they come with risks of disease transmission. Better alternatives include live crickets, superworms, or earthworms. Always ensure any live food is gut-loaded and disease-free.

Juvenile arowanas benefit from being fed 2-3 times a day, small amounts each time. As they mature, feeding once a day or even every other day is sufficient. Always avoid overfeeding, as this can lead to water quality issues and digestive problems.

Water Quality & Parameters: A Pristine Environment

Clean, stable water is paramount for arowana health and growth. Poor water quality is a common problem that can stress fish and inhibit growth.

  • Temperature: Maintain a stable temperature between 75-82°F (24-28°C).
  • pH: Arowanas generally prefer slightly acidic to neutral water, around pH 6.0-7.5, depending on species. Asian Arowanas tend to prefer lower pH.
  • Hardness: Soft to medium hard water (dH 2-10) is usually ideal.
  • Nitrogen Cycle: Keep ammonia and nitrite at zero, and nitrates as low as possible (below 20 ppm is best). Regular, large water changes (25-50% weekly or bi-weekly) are essential to manage nitrates and replenish minerals.

Robust filtration is key to maintaining pristine water. We’ll delve into filtration best practices shortly, but suffice to say, you’ll need more than just a basic hang-on-back filter for these giants.

Genetics & Species: Nature’s Blueprint

While care is vital, the genetic makeup of your arowana also plays a role. As discussed, a Silver Arowana has the genetic potential to grow much larger than a Jardini. Even within a species, some individuals may have a genetic predisposition for slightly larger or smaller growth. Always purchase from reputable breeders or suppliers to ensure you’re getting healthy stock with good genetics.

Stress Levels: The Silent Growth Inhibitor

A stressed fish is a fish that isn’t growing optimally. Arowanas can be sensitive to their environment. Factors that can cause stress include:

  • Aggressive Tank Mates: Arowanas can be territorial; choose tank mates carefully (e.g., large, peaceful cichlids, datnoids, large plecos).
  • Poor Water Quality: Fluctuating parameters or high toxins are major stressors.
  • Lack of Hiding Spots: While they need open swimming space, some cover (like large driftwood or sturdy plants) can make them feel more secure.
  • Over-handling or Constant Disturbances: Keep tank maintenance calm and infrequent once established.

A low-stress environment allows your arowana to thrive, dedicating its energy to growth and health rather than constant anxiety.

Setting Up for Success: Arowana Habitat Best Practices

To truly understand how long do arowana fish get and ensure your fish reaches its potential, you need to plan its habitat from day one. This isn’t just about buying a big tank; it’s about creating a functional, safe, and stimulating environment.

Choosing the Right Tank: More Than Just Gallons

When selecting your arowana’s future home, don’t just look at the gallon rating. The dimensions are far more important. Length and width are crucial for these long-bodied fish that need ample space to turn without scraping against the glass or decor.

  • Length: Aim for a tank that is at least 6-8 times the adult length of your chosen arowana species.
  • Width: A minimum of 2.5-3 feet (75-90 cm) in width is ideal to allow for comfortable turning.
  • Height: While not as critical as length/width, adequate height (2-2.5 feet / 60-75 cm) provides vertical swimming space and helps dissipate jumping energy.
  • Lid Security: Arowanas are notorious jumpers. A heavy, secure, tight-fitting lid is non-negotiable. Any gaps will be exploited.
  • Glass Thickness: For tanks of this size, ensure the glass is sufficiently thick to handle the water pressure and potential impact from a large, powerful fish.

Investing in a high-quality, appropriately sized tank from the start will save you significant headaches and expenses down the line, and is one of the most important how long do arowana fish get tips.

Filtration Systems: Keeping it Crystal Clear

Arowanas are messy eaters and produce a significant bio-load. Over-filtration is not just a recommendation; it’s a necessity for maintaining the pristine water quality they need for optimal growth and health.

  • Sump Filtration: Often considered the gold standard for large fish tanks. Sumps provide massive capacity for mechanical (filter socks, sponges), biological (bio-balls, ceramic media), and chemical (activated carbon, purigen) filtration. They also increase the total water volume of the system.
  • Canister Filters: Multiple large canister filters can be effective for smaller arowana tanks or as supplementary filtration for very large ones. Choose models with high flow rates and multiple media baskets.
  • Internal Filters/Powerheads: Can be used for additional water movement and some mechanical filtration, but shouldn’t be the primary filtration.

Regular maintenance of your filtration system (cleaning sponges, replacing media) is just as important as the system itself. A dirty filter is an ineffective filter!

Aquascaping for Arowanas: Function Over Form

While beautiful aquascapes are appealing, an arowana tank prioritizes function and safety. Remember, these fish need vast open swimming spaces.

  • Substrate: A fine, smooth sand substrate is often preferred, as it’s easy to clean and won’t scratch the fish. Avoid sharp gravel.
  • Decor: Keep decor minimal. Large, smooth pieces of driftwood or rounded rocks can be used, but ensure they are securely placed and don’t create sharp edges or narrow passages where the fish could get stuck or injured.
  • Plants: Live plants can help with water quality, but choose sturdy species that can withstand a large, powerful fish. Floating plants can provide some surface cover, which arowanas appreciate.

The goal is to create an environment where your arowana feels secure but has unobstructed space to move freely and gracefully.

Common Challenges & Solutions in Arowana Growth

Even with the best intentions, keeping arowanas can present challenges. Being aware of these common problems with how long do arowana fish get and knowing how to address them is crucial for your fish’s long-term health and impressive size.

Stunted Growth: Identifying and Correcting the Issue

This is arguably the most heartbreaking problem for arowana keepers. As discussed, stunted growth occurs when the fish’s external body growth slows or stops due to environmental factors, while internal organs continue to develop. This leads to a painful, shortened life.

  • Causes: The primary culprits are an undersized tank, poor diet, and consistently bad water quality. Stress also plays a significant role.
  • Identification: A fish that looks “too small” for its age, has disproportionate eyes, or a compressed body shape, especially when compared to healthy specimens, is likely stunted.
  • Solutions: The most effective solution is early intervention. If you notice signs of stunting, immediately upgrade to a larger tank, dramatically improve diet quality and variety, and commit to rigorous water change schedules. While full recovery is rare, improving conditions can alleviate some suffering.

Prevention is always better than cure here. Plan for adult size from the very beginning.

Fin Rot & Other Health Issues: Prevention is Key

Arowanas, like all fish, can fall victim to various diseases. Many common ailments, such as fin rot, bacterial infections, and ich, are often direct results of poor water quality or chronic stress.

  • Symptoms: Frayed fins, white spots, cloudy eyes, lethargy, loss of appetite, or abnormal swimming are all red flags.
  • Prevention: The best defense is a strong offense. Maintain pristine water quality through regular water changes and robust filtration. Provide a nutritious diet, minimize stress, and avoid overcrowding. A healthy fish with a strong immune system is far less likely to succumb to disease.
  • Treatment: If disease strikes, identify it quickly. Isolate the affected fish if possible and treat with appropriate medications, often in conjunction with increased water changes. Always follow medication instructions carefully.

Regularly observing your arowana for any subtle changes in behavior or appearance is one of the most valuable how long do arowana fish get care guide tips.

“Droop Eye”: A Common Arowana Concern

“Droop eye” (or sometimes “drop eye”) is a condition where one or both of an arowana’s eyes begin to point downwards. While not directly life-threatening, it can impact their vision and is considered aesthetically undesirable.

  • Causes: There’s much debate, but common theories include a diet too rich in fats (causing fat deposits behind the eye), lack of upward stimulation (the fish constantly looks down for food), genetics, or even strong current.
  • Prevention:
    • Feed a varied, high-protein diet that isn’t excessively fatty.
    • Encourage surface feeding to make the fish look up.
    • Consider adding a floating ball or toy to stimulate upward gaze.
    • Ensure adequate tank size and open swimming space.
  • Treatment: Once established, it’s very difficult to reverse. Prevention is key.

Sustainable & Eco-Friendly Arowana Keeping

As responsible aquarists, we have a role to play in the broader aquatic ecosystem. Embracing sustainable how long do arowana fish get practices ensures not only the health of our fish but also the future of the hobby and wild populations.

  • Responsible Sourcing: Always purchase arowanas from reputable dealers who can verify their origin. For Asian Arowanas, ensure they come with proper CITES documentation (Convention on International Trade in Endangered Species of Wild Fauna and Flora), as they are an endangered species. Opt for tank-bred or sustainably farmed specimens whenever possible.
  • Long-Term Commitment: Understand that an arowana is a decades-long commitment. These fish can live for 10-20 years, sometimes longer. Ensure you are prepared for the financial and time investment required for their entire lifespan, including potential tank upgrades.
  • Energy Efficiency: Large tanks require significant energy for heating, filtration, and lighting. Look for energy-efficient heaters, LED lighting, and consider insulating your tank to reduce heat loss.
  • Waste Reduction: Dispose of aquarium waste responsibly. Water change water can often be used to water plants. Avoid pouring medications or chemicals down the drain.

Being an eco-friendly how long do arowana fish get keeper means thinking beyond your tank to the larger impact of your hobby choices.

Benefits of Knowing how long do arowana fish get

Why put so much emphasis on understanding arowana growth? The benefits are immense, both for you as an aquarist and, more importantly, for the welfare of your fish. Knowing how long do arowana fish get empowers you to make informed decisions.

  • Proper Planning: You can plan for the correct tank size, filtration, and equipment from the very beginning, avoiding costly upgrades or the heartbreaking need to rehome a fish.
  • Optimal Fish Welfare: By providing an environment that caters to their adult size, you ensure your arowana lives a long, healthy, and happy life, free from the stress and suffering of stunting.
  • Financial Savings: While large tanks are an investment, they are often a one-time investment. Constantly upgrading or dealing with sick fish due to poor conditions can be far more expensive in the long run.
  • Aesthetic Enjoyment: A healthy, full-grown arowana is a sight to behold. Its natural swimming patterns and impressive size will be the undisputed centerpiece of your home.
  • Credibility as an Aquarist: Successfully keeping such a demanding fish to its full potential demonstrates true expertise and dedication in the hobby.

Ultimately, understanding the growth potential of your arowana is about responsible pet ownership. It’s about giving these magnificent creatures the life they deserve.

Frequently Asked Questions About Arowana Growth

We’ve covered a lot, but let’s quickly address some of the most common questions about arowana growth.

How fast do Arowana grow?

Arowanas grow quite rapidly, especially in their juvenile stage. Many species can grow an average of 1-2 inches (2.5-5 cm) per month during their first year under optimal conditions. Their growth rate slows down significantly as they mature.

Can an Arowana live in a 75-gallon tank?

A 75-gallon tank is far too small for any species of arowana long-term. Even a juvenile arowana will quickly outgrow a 75-gallon tank within a few months. Keeping an arowana in such a small tank will lead to severe stunting, health problems, and a shortened lifespan. A minimum of 180-300 gallons is needed for adult arowanas, depending on the species.

What is the biggest Arowana species?

The Silver Arowana (Osteoglossum bicirrhosum) is generally considered the largest arowana species, regularly reaching lengths of 3 to 4 feet (90-120 cm) in captivity and even larger in the wild.

Do Arowanas stop growing when the tank is too small?

No, not in a healthy way. While their external body growth may appear to stop or slow significantly in a small tank, their internal organs continue to try and grow. This leads to severe health issues, deformities, organ damage, and a greatly reduced lifespan. It’s a form of suffering, not a natural cessation of growth.

How often should I feed my Arowana?

Juvenile arowanas (up to about 10-12 inches) should be fed 2-3 times a day, offering small amounts they can consume quickly. Adult arowanas typically do well with one feeding per day or even every other day, depending on their activity level and the size of the meal. Always ensure you’re not overfeeding, which can lead to water quality issues.

Conclusion

Understanding how long do arowana fish get is more than just curiosity; it’s the cornerstone of responsible arowana keeping. These magnificent fish demand a significant commitment in terms of space, water quality, and diet, but the reward of seeing a healthy, full-grown specimen thrive in your care is unparalleled.

By prioritizing a spacious tank, providing a varied and nutritious diet, maintaining impeccable water quality, and creating a low-stress environment, you’re not just answering the question of their size – you’re ensuring your arowana reaches its full, majestic potential. Remember, planning ahead and making informed decisions are the keys to a successful and rewarding experience.

With the right knowledge and dedication, you’ll be well on your way to cultivating a truly magnificent, healthy arowana that will be the centerpiece of your aquatic world for years to come. Happy fishkeeping!

Howard Parker
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