Do Arowana Need A Heater? {What Are The Ideal Temperature Settings?}

Do you think you may need a heater for your Arowana? Will temperature fluctuations affect their health? In this article, we’ll find out if a heater is necessary for Arowana.

Do Arowana Need A Heater? No. If your climate is warm all year round, then you won’t need to install a heater. If winters get cold indoors, the heater will maintain optimal temperatures of 75-86°F or 24-30°C .

Why Should I Get A Heater For Arowana?

The heater serves multiple functions for your arowana. Consider the following:

  • Temperatures without a heater fluctuate. 
  • Heaters keep water temperatures stable. 
  • Heater are not very expensive. 
  • Heaters are useful when applying medication.

Less Fluctuation

Even if you live in a warmer climate, the air conditioner or ceiling fan could fluctuate the weather indoors. Your arowana are not very sensitive, but they are tropical freshwater fish. Sudden changes in temperature may stress these large fish and cause them to stop eating or become irritable.


Stable temperatures allows your arowana to focus more on rest, feeding and activity. If the temperature is too cold, your arowana will not be able to rest or sleep well. Erratic swimming patterns or constant movement may tire out arowana who try to remain warm.

Cost Effective

The cost of treating your ill arowana due to stress is not worth it if you can mitigate it with the cheap price of a heater. We want these fish to remain comfortable at all times. Heaters don’t cost much in comparison to most other items in the set-up of a tank.

Medicine Friendly

Usually when arowana are ill or ridden with a parasitic infection, raising the temperature along with medicating the tank will help kill off the parasites. Sometimes raising the temperature alone will do the trick. Without a heater, this option is not available.

Which Heater Should I Get For My Arowana?

You have multiple choices on the market. If you’re looking to keep the price low, Eheim or Sera make reliable models for great prices. The most important thing is to make sure there is a heating guard.

Keep in mind, that arowana are powerful fish. They can slam into the glass tubes of the heater causing it to break and possibly harm the scales of these elegant fish.

The thermometer that is on the heater could also break without a proper guard in place. The tank is long and wide so please look for a larger sized heater if possible. Try to operate a heater at over 300w of power.

  • Cheap
  • Heat guard
  • Larger in size
  • 300 watts or more
YouTube video

What Is The Best Temperature For Arowana?

We are trying to replicate the warm tropical waters that our arowana are used to in the wild. 75-86°F or 24-30°C are ideal ranges, but these fish are large enough to handle fluctuations that are 2-3 degrees warmer or cooler.

The pH balance should be between 7.0 and 7.5. Arowana will react negatively to poor water quality. Make sure to perform 25% water changes a week in tank sizes at 150 gallons or larger.

What Happens to Cold Arowana?

An arowana that gets too cold with water temperatures dropping may become skittish or highly stressed. Sudden changes may startle your arowana and cause them to:

  • swim erratically
  • try to jump out
  • become aggressive
  • give up eating
  • become ill

Their immune systems are sure to be affected by the drop in temperature. A heater with a stable temperature setting between 75°-86F or 24-30°C  will make sure this doesn’t happen.

Is the Surface of The Water Warmer For Arowana?

The surface of the water is where the lights are located. These lights give off heat and the outside temperature will also make the water at the top warmer.

If the seasons change or if your room is cold, the surface may not be as warm if the heating tubes are inside the tank. We also don’t want our arowana trying to jump or bump into the glass.

A cover for the tank is common for arowana because they are capable of jumping easily if they are motivated to do so. Some arowana that are stressed may still try to jump and end up injuring themselves off the lid on top of a covered tank.

What Is The Best Tank Size For Arowana?

Although you may find plenty of recommendations for a minimum tank size of 150 gallons, it’s better to get the biggest tank you can fit and afford. 250-300 gallon tanks would allow enough room for 2-3 arowana and give them enough space to turn around.

You can start with 60 gallon tanks when they are juveniles, but they will outgrow it in about a year. If you don’t give them enough space, their bodies may end up physically deformed. The lifespan of your arowana will also be greatly reduced from the stress of being in a small tank.


Arowana can survive in tanks located in tropical countries where the weather doesn’t fluctuate too much. If the ideal temperatures of 75-86°F or 24-30°C are met, then a heater is not needed. Indoor conditions get significantly drier and cooler in warm countries with automatic air conditioners.

It’s best to not take a chance and purchase a cheap heater that has a heat guard to prevent your arowana from breaking the glass tubes. Heaters are also very useful when you need to raise the temperature slightly higher to kill off parasites.


Thank you for stopping by at for all your informational needs concerning the fish you wish to keep in your aquarium. We have plenty of articles on a wide variety of marine life that may also pique your interest. See you again soon!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.

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