How To Cool Down Betta Fish Tank?

my betta swimming

Do you know when Betta fish lovers feel the brutality of the summer the most? When their fish tank gives a feel like it’s on a stove. It can get hotter any day, depending on where and how you keep the tank. But what matters is how fast you’re cooling it down. Now the question is, how to do that?

The best way to cool a Betta fish tank is to move it away from direct sunlight or a heater. Lowering the room temperature or placing a frozen bottle in the tank briefly can also reduce the heat.

But is there any other practical way to cool it down faster? And why cooling it down matters so much? Well, get ready for the answer.

Key Takeaways

  • Reasons like getting close to a heat source, lack of ventilation, wrong lighting, and equipment malfunction can make a Betta fish tank hot.
  • Cooling down the tank is important as it can lead to reduced oxygen levels in water, bacterial growth, and stress.
  • The most effective ways to cool down the tank are removing the heat source, adjusting room temperature, changing tank location, reducing light, and changing water partially. 
my betta fish tank front view

The Top 5 Ways to Cool Down Betta Fish Tank

Okay, there’s no rocket science here. All you have to do is try a bunch of tricks like –

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Removing the Heat Source

There should be an apparent reason why the tank is boiling up. It can be anything like direct sunlight, an unattended heater, or aquarium light. So, once you track the source, get rid of it in the first place.

Adjusting the Room Temperature

If the room temperature played the ‘culprit’ part, adjust it to a comfortable level first. Try using the air conditioner. If that option is not available, use a fan. But don’t leave it unattended as that can lower the temperature too much.

Changing Tank Location

When the sun is boiling up the water just because the tank is close to the window, consider changing the tank’s location. Hold on a second! Not only the window or the sun but if your tank is close to any potential heat sources, change its location or location of the heat sources.

however the larger the aquarium is for your betta fish, the less frequently you have to do water changes

Reducing Light

Depending on the type you’re picking, your aquarium lights can also heat your tank. So, it’s better to lower the light’s intensity and duration as that will generate less heat. Try using LED lights, as they emit less heat than regular ones.

Frozen Bottles

Putting frozen water bottles is something I usually don’t suggest, as too much cold can kill the fish. But if the heat has gone so high that it can kill your fish if you don’t cool it down instantly, this is an option you can try. But make sure you’re not leaving the bottles in there for a long time. And it’s better to let them float so they don’t come in contact with the fish.

Aquarium Cooler

If this heating issue happens too often, spending some bucks on the aquarium cooler is better. As an alternative, you can use a clip-on fan too. Both of these are enough to regulate your tank’s temperature without adding too much to your electricity bill.

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Changing Water

Get some cooler and dechlorinated water to change the tank’s water partially. As changing the whole water can be quite a hassle, partially changing it should be enough to lower the temperature.

my betta tank top view

Why is My Tank Getting Heated?

Clearly, that’s the first question that should come to your mind after seeing a hot tank. But why exactly does a tank get hot? As far as I’ve seen, it happens for the following reasons.

Insufficient Ventilation

Do you know the easiest way to trap heat around your tank?

Doing nothing about the air circulation.

So, it will be tough to keep the tank cool when your tank is placed in a room that can’t let the air out or in.

Wrong Lighting

Some fish lovers think high-intensity light will make the tank’s details more visible. Well, it does, but at the cost of higher heat generation. And yes, the duration also matters here, as a more extended time leads to overheating.

Closeness to Heat Sources

Look around. You’ll see a bunch of electric stuff around you emitting heat. So, if you put your tank close to any of those, the emitted heat can warm up your tank. The same goes for putting the tank close to an open window.

Malfunctioning Equipment

While maintaining a fish tank, you’ll have to use a few equipment, such as filters and heaters. But you never know which one will malfunction and cause the overheating issue you always wanted to avoid.

bettas can die from being too cold. my tip number two is really easy just get a heater... it will always keep it at that balmy 78 to 80 degrees fahrenheit that your betta fish needs to enjoy because he's a tropical fish

Why is Fixing the Heat Issue Quickly Important?

Because –

“A cooler aquarium is a happy aquarium”

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But I don’t think most fish enthusiasts initially take heating issues that seriously, thoughthis can lead to some serious problems, such as –

Reduction in Oxygen Level

If the water is warm, it’s going to hold less oxygen.

So, letting the tank get hot can lower the oxygen level in the water and make the fish super stressed. And if this condition continues, it can mess with their health.

Increasing Metabolism

Initially, this might sound good, but it’s not.

Higher temperatures increase metabolism, so the fish’s activity and food requirements will also increase.

And when you’re putting extra food there, it can end up in overfeeding if you don’t do it carefully.


No matter which pets you name, they are all vulnerable to stress; the same goes for Betta fish.

Keeping them at the right temperature (75-82F°) is one of the best ways to keep them stress-free.

So, when they’re in a tank with a higher temperature, they can become so stressed that it can lead to loss of appetite and lethargy, leaving them vulnerable to diseases.

Bacterial Growth

Whether you ask about bacteria or parasites, they grow much faster in a warmer atmosphere. So, it doesn’t need much explanation of what a hot tank can do to your Betta fish.

Before We Go…

You’re probably wondering if the smaller tanks will be easier to cool down. In a sense, you’re right. But the question is, will it be right to keep your Betta fish in a smaller tank? Well, check out my blog Do Betta Fish Like A  Lot Of Space? And find out which tank size will be the best for your fish.

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Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of I’m passionate about aquarium pets like shrimps, snails, crabs, and crayfish. I’ve created this website to share my expertise and help you provide better care for these amazing pets.


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