Can Oscar Fish And Arowana Fish Live Together?

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I’m truly captivated by both Oscar fish and Arowana fish for their incredible beauty. But the big question is: Can these two stunning species actually share the same tank?

Given the constant curiosity about this, I’ve put together an article to settle the matter.

I’ll explore their behaviors, tank requirements, and whether they can coexist. Let’s get right into the discussion.

Can I Keep Oscar Fish And Arowana Fish Together In The Same Tank?

No, it’s not recommended to keep Oscar fish and Arowana fish together in the same tank. While it is physically possible, it’s fraught with potential issues.

Here are some reasons to consider:

  • Size Disparity: Arowanas can grow up to 3 feet long, while Oscar fish typically reach around 12-16 inches. This size difference can lead to the Arowana seeing the Oscar as prey.
  • Aggression Levels: Oscar fish are known to be territorial and can become aggressive, especially during breeding seasons. Housing them with Arowanas might lead to conflicts and injuries.
  • Dietary Needs: Oscar fish are omnivores, consuming a mix of meaty foods and plants, while Arowanas are primarily carnivorous. Ensuring both species get their specific dietary needs can be challenging in a shared environment.
  • Tank Requirements: Arowanas, due to their size, require large, spacious tanks. Oscar fish, while smaller, also demand ample space due to their active nature, making the combined space requirement quite substantial.
  • Water Conditions: While both Oscar fish and Arowanas require similar water conditions, slight differences in pH or temperature can be crucial for each species’ health, making perfect tank conditions harder to maintain.

Also Read: 19 Great Oscar Fish Tank Mates

Oscar Fish vs. Arowana Fish: Behavior

The first factor worth considering is the Oscars’ and Arowana Fish’s natural behavior. Here is what you should know:

Oscar Fish: Natural Behavior

Oscar fish are popular for their distinctive behaviors and engaging personalities. They interact actively with their owners and have a variety of unique behaviors.

Diving deeper into these behaviors:

  • Territorial Nature: Oscars are fiercely territorial, often displaying aggressive postures and actions when other fish encroach upon their designated spaces within the tank.
  • Interactive Behavior: Oscars develop a keen recognition of their owners, frequently swimming energetically towards the tank surface, showcasing a “begging” behavior when they desire food.
  • Hunting Strategy: Oscar fish utilize a patient approach, lying in ambush before they quickly pounce on unsuspecting prey, such as insects, crustaceans, and smaller fish species.
  • Parental Care: Demonstrating an admirable parental instinct, Oscars diligently guard their eggs, and once hatched, they fan the fragile fry using their pectoral fins to maintain oxygen levels.
  • Curiosity: Showcasing a unique level of curiosity, Oscars frequently exhibit behaviors like rearranging aquarium decorations or persistently digging into the substrate.

Arowana Fish: Natural Behavior

Arowanas, possessing a lineage dating back millions of years, are renowned as predatory “living fossils.”

Predominantly solitary, their behaviors are a testament to their dominant role in the wild. Unpacking their intriguing behaviors:

  • Surface Feeding: Arowanas have developed a specialized hunting technique where they skillfully snatch prey from the water’s surface, which can include insects, small amphibians, or even unsuspecting birds.
  • Jumping Ability: Arowanas, with their powerful musculature, are capable of astonishing leaps, often jumping several feet above the water, a trait that necessitates secure tank lids in captivity.
  • Solitary Nature: Reflecting their dominant status in the wild, Arowanas tend to be solitary creatures, often displaying aggressive tendencies toward other fish, especially those that rival them in size.
  • Parental Mouthbrooding: Male Arowanas showcase a unique mouthbrooding behavior, wherein they safely harbor the eggs, and later, the young fry, within their mouths, shielding them from potential threats.
  • Sensory Barbel: Arowanas possess sensitive barbels on their pronounced lower jaw, an adaptation that aids them in detecting subtle movements on the water’s surface, enhancing their predatory efficiency.

Ideal Parameters For Oscar Fish And Arowana Fish

Proper water conditions are vital for the health and well-being of both Oscar fish and Arowana fish. Here’s a quick comparison of their ideal water parameters.

ParameterOscar FishArowana FishBoth Types
Temperature74°F (23°C) – 81°F (27°C)76°F (24°C) – 86°F (30°C)76°F (24°C) – 81°F (27°C)
pH Level6.0 – 8.06.0 – 7.56.0 – 7.5
Water HardnessSoft to moderately hardModerateModerate

Oscar Fish: Ideal Parameters

Oscar fish are native to South America’s freshwater rivers and require specific water parameters for optimal health.

Ensuring these conditions in a home aquarium is essential for the well-being and longevity of the Oscar fish.

Here are the ideal parameters for Oscar fish:

  • Temperature: Oscar fish thrive in warmer waters, with a temperature range between 74°F (23°C) and 81°F (27°C). Stable temperatures within this range simulate their natural habitat conditions.
  • pH Level: Oscar fish prefer slightly acidic to neutral water. A pH level ranging from 6.0 to 8.0 is ideal for their health and well-being.
  • Water Hardness: Oscar fish aren’t too fussy about water hardness, but generally, a hardness of 5 to 20 dGH (degrees of General Hardness) provides a comfortable environment.

Arowana Fish: Ideal Parameters

Arowanas, being native to the slow-moving waters of Southeast Asia and South America, have specific water parameters that support their natural behaviors and overall health. 

Maintaining these conditions in captivity is vital for their survival and comfort. These are the parameters to consider for Arowana fish:

  • Temperature: Arowanas favor slightly warmer waters. The ideal temperature range for them lies between 76°F (24°C) and 86°F (30°C).
  • pH Level: Arowanas typically thrive in a pH range between 6.0 and 7.5, reflecting the mildly acidic to neutral conditions of their natural habitats.
  • Water Hardness: Suitable water hardness for Arowanas is a bit broader than that for Oscars, typically ranging between 1 to 10 dGH, reflecting the conditions of tropical rainforest waterways.

Also Read: Can Oscar Fish And Silver Dollars Live Together?

Oscar Fish vs. Arowana Fish: Tank Setup

Setting up a tank tailored to the needs of Oscar fish, Arowana fish, or both ensures they thrive in captivity. Here’s a comparative glance at their tank setup requirements.

Setup CriteriaOscar FishArowana FishBoth Types
Ammonia, Nitrite, NitrateRegular monitoring & water changesConsistent quality testsStrict monitoring & frequent water changes
Tank SizeMinimum 55 gallonsMinimum 250 gallonsMinimum 300 gallons (or larger)
FoliageSturdy or artificial plantsTaller plants/floating vegetationMix of sturdy, tall & floating plants
DecorationsHeavy, non-movableMinimal, no sharp objectsAmple space with large, heavy decor
FilterPowerful externalRobust externalHigh-capacity, robust external
HeaterEssential, 74°F-81°FVital, 76°F-86°FCrucial, maintain a mid-range
SubstrateSand and fine gravelFine sand/small pebblesMix of both types
PumpGood circulation pumpStrong water circulationHigh-power circulation pump
LightingStandard, not too brightModerate lightingModerate, balanced lighting

Oscar Fish: Tank Setup

Setting up a tank for an Oscar fish requires understanding their natural habitat in South American rivers.

Properly replicating this environment ensures the Oscar fish’s well-being and active lifestyle in captivity. The key elements to consider for Oscar fish tank setup include:

  • Ammonia, Nitrite, Nitrate: Regular monitoring is essential. Oscars produce a lot of waste, making frequent water changes and tests vital to maintain low ammonia, nitrite, and nitrate levels.
  • Tank Size: Oscars grow large, so they require spacious tanks. A minimum of 55 gallons for a single Oscar is recommended, though bigger is always better.
  • Foliage: While Oscars are not particular about plants, they might uproot them. Sturdy, larger plants or artificial plants are preferable choices.
  • Decorations: Oscars are curious creatures, often rearranging decor. Opt for larger, heavy decorations that they cannot easily move.
  • Filter: Given their waste production, a powerful external filter is crucial. It should process the tank’s water at least 3-4 times every hour.
  • Heater: A reliable heater is essential to maintain a stable temperature between 74°F (23°C) and 81°F (27°C) for Oscar fish.
  • Substrate: A mixture of sand and fine gravel is ideal. This replicates the riverbed substrate of the Oscar fish’s natural habitat.
  • Pump: A good circulation pump helps in oxygen distribution. It should be able to circulate the entire tank’s volume a couple of times an hour.
  • Lighting: Oscars aren’t too particular about lighting. Standard aquarium lighting is sufficient, but avoid overly bright settings which might stress the fish.

Arowana Fish: Tank Setup

Arowanas, due to their size and origin in the slow-moving waters of Southeast Asia and South America, have distinct tank requirements.

Catering to these ensures their health, comfort, and typical behavior patterns in captivity. The essentials for setting up an Arowana tank include:

  • Ammonia, Nitrite, Nitrate: Consistent water quality tests are paramount. High ammonia or nitrite levels can quickly become fatal for Arowanas.
  • Tank Size: Arowanas grow quite large, requiring substantial space. A minimum of 250 gallons is recommended, but as always, bigger is preferable.
  • Foliage: Arowanas prefer some plants for cover, but not dense vegetation. Use taller plants or floating vegetation to mimic their natural environment.
  • Decorations: Keep decorations minimal to provide ample swimming space. Ensure no sharp objects that can harm the Arowana’s delicate barbels.
  • Filter: A robust external filter is a must. It should be capable of handling the tank’s volume multiple times every hour.
  • Heater: Maintaining water temperatures between 76°F (24°C) and 86°F (30°C) is critical for Arowanas, necessitating a reliable heater.
  • Substrate: Fine sand or a mix of sand and small pebbles is ideal. It mimics the soft riverbeds of their natural habitats.
  • Pump: Ensure strong water circulation. A powerful pump that circulates the entire tank’s volume multiple times an hour is recommended.
  • Lighting: Arowanas require moderate lighting. Too bright or too dim might stress them, so finding a balance is key.

The Dietary Requirements Of Oscar Fish And Arowana Fish

Catering to the dietary requirements of Oscar fish and Arowana fish ensures their health and vitality. Here’s a comparative overview of what they need.

Dietary FactorOscar FishArowana FishBoth Types
Food TypesLive foods, high-quality pelletsLive prey, specialized pelletsVariety of live foods, pellets
QuantityConsumed in 2-3 minutesConsumed in 5 minutesMonitor closely, avoid overfeeding
Feeding Schedule2-3 times a day (young), once daily (adult)Once daily (adult), 2-3 times daily (young)Regular intervals, avoid competition

Oscar Fish: Ideal Dietary Requirements

Oscar fish are carnivorous by nature, originating from the freshwater rivers of South America where they actively prey on smaller fish, insects, and crustaceans.

Meeting their nutritional needs in captivity is vital for their growth, health, and vibrancy. Breaking down their dietary needs:

  • Food Types: Oscar fish enjoy a varied diet, which includes live foods like crickets, earthworms, and feeder fish. They also benefit from high-quality pellet foods that cater to their protein requirements.
  • Quantity: Oscars have a robust appetite; however, overfeeding can harm their health. Typically, feed an amount they can consume within 2-3 minutes, ensuring no excess food remains.
  • Feeding Schedule: Feed young Oscar fish 2-3 times a day, while adults are best fed once a day. Consistency in feeding helps maintain their metabolism and energy levels.

Arowana Fish: Ideal Dietary Requirements

Supplying Arowanas with food resembling their natural diet promotes their health and best growth in captivity.

Keep these in mind:

  • Food Types: Arowanas favor diverse foods, such as live prey like tiny fish or shrimp. They also appreciate specific Arowana pellets and occasionally bugs or crustaceans.
  • Quantity: As large species, Arowanas possess significant dietary requirements. Provide food they can finish in 5 minutes and observe for any remnants to avoid contaminating the water.
  • Feeding Schedule: Mature Arowanas typically feed once daily, whereas younger ones might need food 2-3 times a day. Consistent feeding times support their health and promote consistent growth.

Guidelines for Housing Oscar Fish Alongside Arowana Fish

Co-housing Oscar fish and Arowana fish in the same tank can pose challenges due to their territorial and predatory behaviors.

Yet, with suitable tactics and measures, one can mitigate potential disputes and ensure a harmonious environment.

For this balance, keep in mind:

  • Tank Dimensions: Choose a roomy tank, at least 250 gallons. This provides both Oscar fish and Arowanas sufficient room to claim territories and minimize constant contact.
  • Territory Indicators: Incorporate dividers or employ big decorations to form clear territories. This can reduce potential clashes between Oscars and Arowanas.
  • Joint Entry: Introducing both fish species simultaneously can diminish territorial disagreements. Without pre-claimed zones, both Oscar and Arowana can find their spots without altercation.
  • Routine Observation: Monitor their actions frequently, especially during meal times. Spotting early signs of aggression or other problems can prevent them from worsening.
  • Feeding Approach: Serve food at distinct ends of the tank or utilize a feeding circle for the Oscar. This reduces food-related competition and possible feeding disputes.
  • Sufficient Shelter: Ensure the presence of adequate hideaways like caverns or thick vegetation zones. These offer Oscar fish a safe haven from the possibly dominant Arowana.
  • Consistent Water Care: Maintaining stable and pure water conditions diminishes stress. Heightened stress can intensify aggressive behaviors in both Oscar fish and Arowanas.

Also Read: Can Oscar Fish And Discus Fish Live Together?

Should I Opt for an Oscar or an Arowana Fish

Choosing between an Oscar fish and an Arowana largely depends on your aquarium setup, your experience level, and your aesthetic preferences.

While both are captivating in their own right, they come with distinct care requirements and personalities. Factors to consider when making your choice include:

  • Tank Size: Oscar fish require a minimum of 55 gallons, while Arowanas need significantly more space, ideally starting at 250 gallons. Consider the size of your aquarium and future expansions.
  • Budget: Arowanas are typically more expensive, not just in terms of initial purchase but also in terms of tank setup and maintenance. Oscar fish, while still requiring good care, can be less burdensome on the wallet.
  • Care Level: Oscar fish are often recommended for intermediate aquarists due to their robust nature. Arowanas, with their specific needs and sensitivity, might be better suited for more experienced hobbyists.
  • Lifespan & Growth: Oscars can grow up to 12-18 inches and live around 10-15 years, while Arowanas can exceed 30 inches and have a lifespan of 15-20 years. Consider the long-term commitment and space requirements.
  • Interaction & Personality: Oscar fish are known for their playful nature, often interacting with their owners. Arowanas are more independent and regal but can be equally fascinating to observe.


For those of you who are just skimming through, here’s a short recap:

  • Oscar fish and Arowana fish shouldn’t share a tank due to size differences, aggression risks, dietary conflicts, demanding tank needs, and delicate water conditions.
  • Oscar fish are lively and territorial, engaging with owners, while Arowanas, ancient predators, are solitary jumpers with unique mouthbrooding habits.
  • Oscar fish thrive at 74°F-81°F, pH 6.0-8.0, and soft to moderate water hardness, whereas Arowanas prefer 76°F-86°F, pH 6.0-7.5, and moderate hardness.
  • Proper tank setups involve large spaces, strong filtration, and cautious decor for Oscar fish, while Arowanas need spaciousness, minimal decor, and tall plants.
  • Feeding differs; Oscars enjoy live foods and pellets in moderation, while Arowanas need live prey, pellets, and insects, adhering to appropriate schedules.