Do Bettas Need a Heater?

Written By Lewis German  |  Tropical Fish  |  0 Comments

Plants for Betta Fish

Bettas are one of the most commonly kept species of tropical fish out there, but they are often kept in very small containers without a filter or a heater.

Is this the right way to keep them? Do Betta fish need a heater? What temperature should Bettas be kept at? And are they able to live in coldwater?

Continue reading to find out;

Can Bettas live in cold water?

Despite being able to survive in cooler water on occasion, Bettas are not “coldwater fish” as they are used to living in tropical to subtropical waters, which typically stay well above average room temperature (20C / 68F).

To be considered coldwater, it would have to be consistently lower than 20C, and would have frequent dips in temperature throughout the year, regularly dropping lower than 15C / 59F.

Bettas cannot live in a coldwater environment, and can die if kept in a draughty room which gets cold frequently.

Can Bettas live in a tank without a heater?

On some occasions, it is possible to keep your Betta in an unheated tank, but this would be dependent on the surrounding ambient temperature, which would need to stay above 23C / 72F consistently.

For most people however, a heater is necessary, as it gives for better control over the fish’s environment, and allows you to maintain a healthy tank temperature.

In the case of Bettas, this is extremely important, as many people tend to keep them in small tanks which lose heat very quickly.

Heavy fluctuation in temperature causes immense stress on Betta fish, and can kill them easily, so it is very important that you make an effort to keep a stable temperature through the use of an aquarium heater.

How long can Bettas survive without a heater?

Depending on the situation, this answer will vary, but for most people, especially those who live in a temperate area and keep their Betta in a small tank, their fish may not survive very long without a heater.

Larger tanks hold onto heat for longer, so in a 20 or 30 gallon tank, you may have a couple of days before you start to see the effects of the cold.

In a small 5 to 10 gallon tank however, it may only be 24 hours before you begin to see your Betta become sluggish and start to succumb to the effects of the cold.

Why do Bettas need a heater?

Bettas need a heater because they originate from tropical parts of Southeast Asia, where it stays very warm throughout the year.

They have evolved to live in an environment which regularly stays around 27C / 81F, and so when kept in a much cooler habitat, they struggle to cope.

Using a heater allows you to create a habitat that closely mimics the hot weather that Thailand is frequently subject to, and makes for a more natural, healthy environment for your Betta.

What temperature should a Betta tank be?

Bettas like to be kept warm, and are most comfortable when in a heated tank anywhere from 23C / 73F to 27C / 81F.

It is possible to keep them outside of these temperatures, but this range seems to work the best for promoting optimal health, as it mimics the warm waters of Thailand where Bettas originate from.

Types of aquarium heaters for Betta tanks

Any type of aquarium heater will work with your Betta, however, tank size may be limiting when it comes to what you should and shouldn’t use.

Glass heaters are the best option for Betta tanks, as they come in a variety of sizes and can be fitted into smaller tanks easily.

They are very easy to install; simply submerge the heater fully in the tank, and place it at a 45 degree angle.

It is best to suspend the heater or use sticky suction cups to attach it to the back of the tank.

When it comes to choosing the right size, simply correlate the wattage of the heater with the literage of the tank, for a 45 litre tank, use a 45 watt heater, and so on…


FAQs about heating Betta tanks

How do you test the water temperature in a Betta tank?

You may use a range of tools to test the temperature of your Betta tank, thermometer tape, glass probes, etc.

However, one of the easiest and most accurate methods of testing the temperature is through the use of a digital thermometer.

Submersible LCD screen thermometers are great for small tanks, they accurately determine the temperature, and display it on an easy to read, clear heads up display, constantly giving a pinpoint reading.


Do Betta fry need a heater?

If you wish to breed Bettas, then you need to ensure that the young stay warm, and are kept at a similar temperature to the adults.

Betta fry are tiny, and lack the fat reserves to cope with strong dips in temperature, they are highly vulnerable in their early stages, and a sudden cold spike could kill them.

For this reason it is very important that a consistent, stable temperature is maintained, using an aquarium heater at this stage is highly advised.

What happens to Bettas if the water is too cold?

As the surrounding water begins to cool down, so will the fish’s body temperature, and in response, their metabolic rate will slow.

Bodily functions will begin to gradually shut down and activity levels will drop as a method of conserving energy.

While Bettas are able to slow down their bodies as the temperature drops, they cannot enter a full state of hibernation like many coldwater fish can.

They have their limits, and once the water becomes too cold, they will begin to suffer from organ damage, and will eventually die unless the water warms up again.

What happens to Bettas if the water is too warm?

Once the water becomes too warm for your Betta, they will do the opposite, and will speed up their bodily processes, they will become more active, will digest food quickly, and will need to eat more.

Having a faster metabolism speeds up the lifespan of the Betta, they will grow much faster and may become much larger than normal, but will live shorter lives if kept at high range tropical temperatures.

Eventually the water will become too warm, and once past 32C / 90F, they will suffer from heat stress, and will become sluggish and weak, eventually suffering organ damage.

Unless the water cools down back to stable levels, or they can escape to a cooler area, they will perish.