Arowana Care Sheet

Arowanas require large tanks, high water quality, and an experienced fish keeper due to their size and sensitivity.

This care sheet outlines basic care needs for a variety of arowana species, including the silver and jardini arowana.

Species Overview

Arowanas are large, prehistoric freshwater fish known for their size, growth rate, and sensitivity to water quality.

They are found in tropical waters across South America, Asia, Australia, and Africa. In some cultures, certain species symbolize health, good luck, and prosperity.

They can grow up to 2 inches per month during their first year and reach over 3 feet in adulthood. 

Arowanas are highly specialized predators, and use their long, whisker-like barbels near the bottom of their mouths to sense movement on the water’s surface.

Due to their large size and aggressive nature, arowanas are best suited for experienced fish hobbyists.

Arowana Characteristics 

Supply Checklist

To care for an arowana, you need a large aquarium and essential equipment to maintain water quality and habitat stability.

• Appropriately sized aquarium  

• Appropriate fish food, dry and frozen  

• Décor  

• Water conditioner  

• Filter  

• Water test kit  

• Full-spectrum lighting  

• Hood  

• Net  

• Thermometer  

• Freshwater substrate    

• Heater   

• Airline tubing  

• Air stone  

• Air pump  

• Check valve  

• Freshwater salt  

• Refractometer or hydrometer 

Habitat

Arowana Tank Size

Arowanas require a tank of at least 150 gallons, with enough space to accommodate their long bodies and active swimming behavior.

Since arowanas swim near the top of the tank, length and width are more important than height.

Ideally, the tank should have a large bottom surface area (“footprint”) so the fish can swim and turn comfortably. Always provide the largest habitat possible.

Arowanas are powerful jumpers, especially when startled, so the tank should be secured with a fitted aquarium hood to prevent injury. Gradually lighting the room before turning on aquarium lights may also help reduce stress and sudden jumping behavior.

Place the tank in a quiet area of your home, away from direct sunlight, windows, and air conditioners.

Arowana Tankmates 

Arowanas are solitary fish and should usually be kept alone to prevent aggression and stress.

If housed with other fish, tankmates must be large and bottom-dwelling so they are not eaten or competing for space.

Filtration 

Arowana tanks should have strong filtration that processes the tank’s full volume at least four times per hour.

For example, a 150-gallon tank should have a filter rated for at least 600 gallons per hour (GPH). If only a 550 or 700 GPH filter is available, purchase the 700 GPH option.  

Power filters (“hang-on-back”) and external canister filters are recommended because they provide mechanical, biological, and chemical filtration and do not take up as much space.

The water should have moderate to strong circulation to mimic natural conditions.

Air stones, air pumps, and airline tubing can improve oxygen levels and water movement.

Water Health and Salt Content  

Arowanas require stable water quality with frequent testing to maintain safe pH, ammonia, nitrate, and nitrite levels.

Arowanas are sensitive to nitrates and require nitrite levels as close to zero as possible. An aquarium test kit, like the API 5 in 1 Freshwater & Saltwater Aquarium Test Strips, should be used regularly to monitor water parameters.

Adding freshwater aquarium salt may support gill health. If used, maintain specific gravity at 1.004 and avoid fluctuations greater than +/- 0.001 in 24 hours.

A hydrometer or refractometer should be used to measure salt concentration.

Temperature 

Arowanas thrive in water temperatures between 72–82 F and require stable heating.

Use an aquarium heater with a thermostat to maintain temperature and prevent fluctuations greater than +/- 2 degrees F per day.

As a rule of thumb, aquarium heaters should have between 2.5–5 watts of power for every gallon of water in a tank. Example:

• 150-gallon tank → 375–750 watt heater

Pet parents can place two heaters on opposite sides the tank to prevent cold spots. 

Check the water temperature daily with an aquarium thermometer. 

Tank Decor and Accessories 

Arowana tanks should include minimal décor to allow for swimming space while still providing enrichment.

Plants and driftwood can be added to create hiding spaces, though arowanas spend most of their time near the surface.

Ensure décor is secure and does not overcrowd the tank. Submerged plants should be anchored to prevent tipping and injury.

All décor should be rinsed thoroughly before adding to the tank.

Cleaning & Maintenance

Arowanas require regular tank cleaning and partial water changes to maintain safe water quality.

Pet parents should perform routine water changes of 10–25% every two to four weeks.

Avoid replacing all the water at once, as this removes beneficial bacteria that keep the tank ecosystem healthy.

Most fish tanks require a full cleaning about once a month, depending on stocking levels. Be sure to test water frequently to monitor quality

To clean an arowana tank, follow these steps:

1. Wash your hands thoroughly and ensure there are no lotions, perfumes, or chemicals present.
2. Do not remove your fish from the tank, as this can cause stress or injury.
3. Use a soft sponge or scrubber to clean the inside walls of the aquarium. Use acrylic-safe tools for acrylic tanks to prevent scratches.
4. Remove décor and artificial plants with heavy algae buildup.
5. Scrub décor using an algae pad and hot water.
6. If needed, soak décor in a diluted 3% bleach solution for 15 minutes, then rinse thoroughly until no odor remains and allow to air-dry completely.
7. Inspect the filter and clean it according to manufacturer instructions if needed. It’s recommended to replace filter media monthly or rinse it in old tank water during water changes, depending on tank conditions.
8. Use a siphon vacuum to remove waste and old food from the substrate while draining water.
9. Ensure all décor is fully dry and free of bleach odor before returning it to the tank.
10. Add fresh, dechlorinated water to replace removed water, ensuring it matches the tank’s temperature. The new water must be detoxified with a water conditioner to remove toxic chemicals like chlorine, chloramines, and heavy metals
11. Use an aquarium-safe cleaner on the exterior of the tank. Household cleaners should be avoided, as they often have ammonia and other chemicals that are toxic to fish. 
12. Check the aquarium’s filter, water temperature, and equipment daily to ensure proper operation.

Diet & Nutrition

Arowanas require a high-protein, carnivorous diet.

A nutritious and well-balanced diet for an arowana includes:

• Floating pellets or sticks designed for surface-dwelling carnivorous fish
• Live, frozen, or freeze-dried fish, insects, worms, and shrimp

Adults can be fed once daily, while young arowanas should be fed two to three times per day. Do not give young arowanas insects or invertebrates with sharp or hard shells.

At each feeding, fish should consume all food within one to two minutes.

Frozen foods must be thawed before eating.

Veterinary Care

When caring for an arowana, monitor health regularly and consult a veterinarian when signs of illness appear.

Annual and Preventive Care

In a properly maintained tank, veterinary care is usually only needed if a problem occurs.

However, it is recommended to have your arowana and tank setup evaluated by a veterinarian within the first week after bringing your fish home.

Whenever possible, work with an aquatic veterinarian who can make house calls, as transport is stressful and adult arowanas are often too large to move safely.

Signs of a Healthy Arowana

• Clear eyes
• Full range of fin movement
• Intact fins with no discoloration
• Regular and active swimming pattern
• Strong appetite
• Swimming near the top of the water column

When To Call a Vet for Your Arowana

Contact a veterinarian if you notice any of the following signs:

• Changes in coloration (dullness, spots, stripes, or bands)
• Lethargic or abnormal swimming (circling, listing, staying at the bottom)
• Receding fin edges with or without discoloration
• Decreased appetite for more than one day
• Itching or rubbing behavior
• Rapid breathing or flared gills
• Gill color changes
• Lumps, bumps, or masses
• White growths or spots
• Cloudy or bulging eyes
• Raised scales
• Weight loss
• Bloating

Common Arowana Health Problems

• Fin or tail rot
• Dropsy (fluid-filled body cavity)
• Parasites
• Bacterial infections
• Cancer
• Ich
• Pop eye
• Fungal infections (oral or skin)
• Swim bladder disorders