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How to Keep Betta Water Warm Without a Heater

Lindsey Stanton Profile Picture

By Lindsey Stanton

betta fish

Today, we are focusing on how you can keep your Betta tank water warm without using a heater. To be clear, it is advisable to get even a basic heater for your Betta due to their temperature requirements. But if for whatever reason you do not have a heater, these tips should serve as a temporary solution for you.

Betta fish generally need a consistent temperature of up to 80 degrees Fahrenheit to stay happy and healthy, and the only real way of achieving that is by adding a heater (a 25-watt heater in a smaller tank of 3-5 gallons, as an example). We created this article for anyone who doesn’t have a heater right now but is planning to add one. This should serve as temporary assistance, but please do ensure you get a heater, as it is necessary. The Penn Plax Submersible heater is a great option!

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The 5 Temporary Ways to Keep Betta Water Warm Without a Heater

1. Use the Hood/Canopy

One of the easiest ways to ensure that your Betta water  stays warm is to use the hood or canopy for the tank. In layman’s terms, put a lid on your tank. If you put a lid on your tank, the water will retain heat better, as it will not dissipate out through the water’s surface as much as it would without a lid.

Yes, if you put a lid on your aquarium, it might make accessing the interior a little harder, but most hoods come off quite easily, so it should not be a huge issue. Moreover, if you are worried about oxygenation, you can always add an air stone into the tank if you have one. This way, even though there is limited air coming into the tank, the air stone will more than make up for the deficiency.

2. Use a Stronger Light

Another way you can ensure that your Betta tank’s water stays warm is to make use of the lights. Aquarium lights, at least certain ones, tend to give off a fair amount of heat. Not only are lights good for illumination, for making your Betta fish feel at home, and for plant growth, but they’re also good for providing some extra warmth.

A light running for 8 or 10 hours per day will definitely heat the water a fair bit. If the light you currently have is not strong enough, you can always jack up the amount of illumination for a while.

However, when doing this, you do need to be careful of temperature changes, as when the light turns off, the temperature will start to decrease a little bit. It is all about finding a good balance here.

image of the glass aquarium tank with water plants and has a bright LED lamp on top
Image Credit: BLUR LIFE 1975, Shutterstock

3. Keep It in a Warm Area

One easy way to help your Betta tank water increase in temperature without using a heater is to simply keep the tank in a warmer place. Chances are that some areas of your home are warmer than others. For instance, if you have a two-story home, the story that is higher up will generally be warmer than the one lower down. This can make a difference of a few degrees, at least.

Also, if you place the tank in an area where there is limited airflow, there will not be much of a breeze, which causes heat to dissipate from the tank. Finally, if you can find an area of your home that is generally sunny during the day, you can place the tank there too.

Even if it just gets 5 or 6 hours of sunlight per day, it should be more than enough to significantly increase the temperature of the Betta tank water. When dealing with real sunlight, you might have to take some steps to combat algae growth, as algae bloom in lots of sunlight (more on removing algae from your tank over at this article).


4. Use a Filter That Is Not Energy Efficient

Using a filtration system that runs warm and uses a fair bit of energy is one way to keep the tank a little warmer than it would be otherwise. Things like filtration units that are not energy efficient tend to run hotter than energy-efficient filters. The heat created by the filter’s motor will work to heat the water a little bit.

5. A Smaller Tank

This is kind of a dual-edged sword, but it still works. Larger bodies of water take longer to heat up than smaller bodies of water. Therefore, if you have a smaller Betta tank, it will heat up faster.

However, heat will also dissipate quicker, which is the dual-edged sword we mentioned before. This solution can be a little tricky to master. Also, we would not recommend anything lower than 3 gallons as the smallest tank size.

If you need some help finding the right Betta tank, we have covered a very detailed buying guide, which you can find here.

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As you can see, there are quite a few temporary solutions that you can go with to keep your Betta fish tank fairly warm without a heater. We really recommend getting a heater for your Betta tank as soon as you can. It’s essential to ensure your Betta is healthy and has the right living conditions.

Featured Image Credit: Mr.Soonthorn Thonglor, Shutterstock

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