Can Betta Fish Live In Cold Water? (Bettas Temperature Guide)

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One of the first questions I had, when I found out I would have a betta fish, was whether he could live in cold water. So naturally, I did some research. Luckily, I gathered the information before exposing my betta to the cold.

Betta fish can live in cold water, although that will harm their health and general state. The ideal temperature for bettas is 78-80°F. Anything below 72°F will compromise their metabolism and immune system. Bettas living in too-cold water usually appear lethargic and show no interest in food.

As we move forward, I will show you what signs your betta is likely to present when its environment is too cold. Then, I will elaborate on how long bettas can actually survive in cold water and what threshold might ultimately kill the fish.

Also Read: Facts About Bettas

Can Bettas Live In Cold Water?

Yes, betta fish can live in cold water. But it won’t be pleasant. Additionally, you shouldn’t expect the bettas to survive in the long run. Bettas are tropical fish. In the wild, they are accustomed to warm conditions. In a tank, you have to keep them in water whose temperature ranges from 75 to 80 degrees F.[1]

This is why aquarists are discouraged from keeping bettas in small containers such as cups. Yes, bettas are labyrinth fish, which means that they can technically survive in small containers, at least for a time. They can rise to the surface to take gulps of air if the need arises.

That being said, a small container, such as a cup, is a problem because you cannot install heaters and filters. The fish is at the mercy of the ambient temperature. This is not an issue if you live in a tropical region with ambient temperatures that can keep the water in the cup within the 75 to 80 degree F range. Normal room temperature is not suitable for Bettas. It is too cold.[2]

But even if the ambient temperature in your home is suitable for bettas, you cannot rely on that ambient temperature to stay the same. For instance, once night falls, the ambient temperature will drop. And if you did not know, aquarium fish hate drastic changes in parameters like the pH and temperature.[3]

If the ambient temperature is constantly fluctuating, the temperature in the tank will also fluctuate, and your bettas will suffer. A heater allows you to control the temperature. You cannot install a heater on a small container like a cup.

Admittedly, bettas can survive the poor conditions that a small container attracts. But they won’t be happy. Where the temperature is concerned, it won’t take you long to realize that the cold conditions have induced stress in your bettas. 

You will also find that they are more susceptible to illnesses like fin rot because their immunity is much weaker. Simply put, bettas can live in cold water for a time. But the cold water will make them sick and miserable. Eventually, they will pass away.

What Happens When Betta Fish Get Cold?

Bettas are tropical fish, which means that putting them in cold water will have negative consequences. This is what you can expect:

1. Your Betta Will Be Susceptible To Diseases

The betta’s immune system will suffer. It will simply deteriorate. As a result, the betta will become more vulnerable to infections and parasites.[4] Most bettas will fall sick if they are forced to live in dirty tanks because they are exposed to so many pathogens.

A betta in a clean but cold tank can fall sick just as easily because the creature’s immunity is not strong enough to combat the few dangerous parasitic pathogens and bacteria to which it is exposed. If your tank is well maintained, but your bettas are always falling sick, the temperature might be the cause.

2. The Betta Will Be Inactive

Do not expect a betta in cold water to fall sick immediately. It may take a while for the creature’s immunity to weaken. Lethargy is one of the first symptoms you will observe. This is true for most aquarium fish. Because they are cold-blooded, they will respond to cold temperatures by becoming less active.

They will start by swimming sluggishly. Then, they will spend less time swimming and more time resting. If the cold temperatures persist, they will stop moving altogether. You may see them hovering near the bottom or lying on their sides because they cannot muster the strength to move.

Lethargy is a symptom of disease and stress. But you should check the temperature before concluding that the bettas are resting at the bottom because they are sick or stressed. In the worst-case scenario, a betta in cold water will slip into a coma.[5]

This is because the betta’s bodily functions have become so slow that the creature’s brain cannot get enough oxygen. But the betta is not beyond saving. Despite what your instincts may tell you based on your observations, the fish is not dead. You can save it from the temperature shock by raising the temperature of the water.

3. Your Betta’s Metabolism Rate Will Drop

Cold temperatures will affect a betta’s metabolism, causing it to drop.[6] This is the reason why a betta in cold water becomes less active. Warm water does the opposite. It makes the fish more active by raising their metabolism. Fish in warm water eat a lot more than fish in cold water.

Because of the warmth, the digestive processes of the fish in question will speed up. As such, cold water might sound like a blessing for aquarists whose fish produce too much waste because cold water will reduce the amount of food they consume, cutting their waste products in the process.

But this reasoning is not quite as sound as you think. Because cold temperatures cause the digestive system to function slower, cold water is associated with digestive ailments like constipation.[7] This can lead to swim bladder disease. The fish will get fatter and less active.

If that wasn’t bad enough, a betta that has become inactive because of a drop in the creature’s metabolism would also stop eating. Like humans, fish require food to survive. If your betta stops eating because of the cold water, it will die.

How Cold Is Too Cold For Betta Fish?

Temperatures below 74 degrees F (23°C) are too cold for betta fish. At that point, you will observe tangible symptoms of temperature shock. Generally, the ideal temperature for a betta fish tank is 78 to 80 degrees F, but they can live in water as cold as 76 degrees F.

It is worth noting that a new betta in a tank with the right temperature (78 to 80 degrees F) can also experience temperature shock if the aquarist forgets to acclimate the creature. As was noted before, bettas do not appreciate drastic changes in their parameters.

If a new betta was accustomed to the wrong temperature in a different tank, it might respond negatively to the right temperatures in a new tank because of the stress caused by the transition. Keep this in mind before you add new bettas.

Also Read: Do Bettas Prefer Long Or Tall Tanks?

How Long Can A Betta Fish Live In Cold Water?

Betta fish will survive for three to six months if the water is just a few degrees below the ideal range (78-80°F). However, freezing temperatures (below 72°F) will kill your betta in a couple of days. The ability to endure cold temperatures mainly depends on the fish’s health condition.

Bettas won’t be happy in cold temperatures. They will become sick and lethargic. You will also see the discomfort in their behavior. They may stop eating altogether. But the fact that they can survive for so long means that you have a chance to help them.

You can start by installing a heater. But the obvious solution isn’t to crank that heater all the way up. You don’t want to make their situation worse by forcing them to endure a drastic temperature change. It could kill them.

Raise the temperature gradually. Depending on how cold the water is, it could take you several days to raise the temperature to the required point. This sounds tedious, but it is necessary, especially for bettas who have been living in the cold aquarium for several weeks. Don’t forget to include a thermostat if the heater doesn’t have one. You need to keep an eye on the temperature.

What if you don’t have a heater on hand, and you don’t expect to get one anytime soon? You can still raise the temperature by placing a cover over the tank.[8] This will permit the aquarium to retain more of its heat.

If you are worried about restricting the gas exchange that happens at the top, add a water stone to prevent oxygen deficiencies from threatening your sick and stressed bettas. If the tank is still too cold, add some intense lighting.

Lights generate heat. In fact, many aquarists will disable the lights in their aquarium during the summer to prevent overheating. Therefore, you can trust a strong light to raise the temperature in the tank. You can also trust them to raise the temperature gradually.

Don’t forget to include a decent filtration system. It will prevent the water from becoming too stale. Interestingly enough, even though fish do not like small tanks, a small tank can help you if your bettas are too cold.

You can generate warmth at a faster rate in a small tank. It takes a while for the warmth to diffuse through a large tank. If you’re truly desperate, you should consider moving the betta to a smaller bowl. It will survive long enough for you to get a heater for your large tank.

What Temperature Will Kill Bettas?

Temperatures below 72 degrees are likely to kill bettas. While the ideal range is 78 to 80 degrees F, fish can survive in temperatures as low as 72 degrees. They won’t like it, but they can survive. But once the temperature falls below 72 degrees, you could lose your bettas within the hour.

As I mentioned earlier, bettas require a heater. I personally use the Orlushy Submersible Aquarium Heater (link to Amazon). After testing countless devices, I genuinely believe that this is the one you should get. It keeps the temperature incredibly stable. The price is also reasonable.

What Is The Maximum Temperature For Betta Fish?

The maximum temperature for betta fish is 84 to 86 degrees F. Bettas can handle temperatures that are a little higher than the ideal range. They’ll be uncomfortable, but they will survive. However, temperatures higher than 86 degrees F can be fatal.

Bettas that suffer from heat stress will have difficulty breathing. They might even die because of the lack of oxygen. You need to remove the betta if the temperature breaches 85 degrees F for several hours or a day. Ideally, you should check the temperature of your aquarium every few hours.

Other symptoms of heat stress include lethargy and inactivity. The fish will stop eating. They will probably float near the bottom of the tank. The long-term solution is to find a place that offers a cooler temperature. Alternatively, slowly decrease the temperature by using ice cubes.

Also Read: How Many Betta Fish In A Tank?


If the water in your aquarium is below 72 degrees, you could lose your betta in a couple of days. If you have a heater, you can raise the temperature gradually until it reaches the optimal level (78 to 80 degrees F). If your betta is healthy, it should survive.

But if you don’t have a heater or one working correctly, I highly suggest that you get one. A cold aquarium can be fatal to your betta fish. You don’t have to use the heater all the time, but you should use it occasionally to sustain a constant temperature.