Betta Fish Water Temperature

Betta Fish Water Temperature: Getting it Right the First Time

Many people across the world keep Betta fish in their home aquariums. The fish is very popular because of its bright colors and its feather-like fins that are very pleasing to view.

The fish are native to the South-East Asian country of Thailand. They are normally found in slow-moving waters such as ponds, streams, swamps, and big rivers in the country. They are also found in rice paddies and roadside ditches.

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The fish have been successfully introduced in the wild in countries such as Brazil, Malaysia, Colombia, and Indonesia. Apart from wild populations, the fish are artificially bred in many Western countries and sold as pets. 

Traditionally, Betta fish were bred to fight each other. This is because the male Betta fish are very territorial and will fight each other when put in a confined space such as a tank. People used to put them in water tanks to fight and crowds even used to bet money on which one would win. Because of this history, Betta fish are also known as Siamese fighting fish. 

Keeping Betta fish as a pet is something that you will love doing. This is because they are fun and lovely-to-look-at low-maintenance pets. You can actually play with them. However, even if they are low-maintenance pets, you still have to take good care of them to make sure they thrive and stay happy and healthy. And taking good care of them includes making sure you keep them at the perfect water temperature. 

Best water temperature for Betta fish

The perfect water temperature for this fish species is around 78 to 80 degrees Fahrenheit. This is the perfect water temperature for Betta fish because they are tropical fish. They are native to Thailand which has a tropical savanna climate. So they are used to the kind of average tropical temperatures witnessed in Thailand. 

Many people believe that the Betta fish sold as pets in the Western world have been domesticated for so long that they no longer require tropical temperatures. This is not true.

Many studies and experiments have shown that domesticated Siamese fighting fish thrive in tropical temperatures. This is proof that they still require tropical temperatures even in aquariums. Hence, you should make sure the water temperature of your aquarium is between 78 and 80 degrees Fahrenheit.

Can the fish species survive in temperatures below 78 degrees Fahrenheit and higher than 80 degrees Fahrenheit? Yes, they can. But they will be just “surviving”. If you have one or two Betta fish in your aquarium and you want them to thrive, maintain the 78 to 80 degrees Fahrenheit range. 

What temperature is too hot for Betta fish?

As mentioned above, Betta fish thrive at temperatures between 78 and 80 degrees Fahrenheit. Anything above 80 degrees and they will be surviving and not thriving. However, if the water temperature in your aquarium exceeds 86 degrees, your pet fish will no longer be surviving; it will be cooking albeit slowly. So 87 degrees Fahrenheit and above is too hot for Betta fish. It is physical and mental torture. 

When the water becomes too hot for your Betta fish, you will notice it starting to behave abnormally. For instance, it can start swimming in an abnormal pattern or it can become overactive and start swimming faster than usual.

If you notice any abnormal behavior in your fish’s swimming patterns, you should know that something is wrong and you should act immediately to correct it. If you leave your Betta fish in hot water for too long, it can die. If it does not die immediately or after some days, it can acquire diseases that will make it weak and lethargic. 

What temperature is too cold for Betta fish?

Again, as mentioned above, Betta fish thrive at temperatures between 78 and 80 degrees Fahrenheit. Anything below 78 degrees Fahrenheit and they will be surviving and not thriving. If your aquarium temperature goes below 74 degrees, it will be too cold for your Betta fish. And it will affect the fish negatively. 

The difference between 74 and 78 degrees may seem small but it is not. If you have a remote-controlled air conditioner, try reducing the temperature in your home by about four degrees from the normal. The difference will be so significant that you will probably want to put a sweater on. Now imagine what your cold-blooded pet is feeling when the temperature reduces by four degrees from its ideal minimum temperature. The poor thing will be freezing. 

Hence if you decide to keep a Betta fish or if you already have one, you should commit to being a responsible fish pet owner and maintaining your aquarium temperature at the ideal temperature range. 

Important facts about the water temperature in your aquarium

You should keep in mind the fact that the water temperature in your aquarium is not the same as your room temperature. It is several degrees lower than your room temperature. So you cannot just assume that the temperature you set on your thermostat or air conditioner is the same temperature in your aquarium. 

This is why it is important to buy and have an aquarium thermometer. This will tell you the exact temperature of the water in your aquarium and you will know for sure if it is too hot or too cold for your Betta fish using the information you have learned today.

How to change the temperature of aquarium water

Now that you know the ideal temperature range for your Siamese fighting fish, it is time to learn something else that is very important. And that something is how to change the temperature of the water in your aquarium. This is very important because most types of fish including Betta fish are quite sensitive to sudden temperature changes.

Therefore, if you attempt to change the water temperature by several degrees at once, you could kill your pet fish. If you do not kill it, you could stress it significantly resulting in shock or bloating.

The trick to changing the temperature of your aquarium water safely is to do it slowly or gradually. When changing the temperature of your aquarium, you should change it by no more than one degree a day. This may seem slow and tedious but it is the best way to ensure your pet survives the temperature change.

To change the temperature, you will need two key things – an aquarium thermometer and an aquarium heater. An aquarium thermometer is what will tell you exactly if your aquarium is too hot or too cold for your fish. Once it tells you the precise temperature, the next step is to use your aquarium heater to adjust the temperature gradually. 

There are many aquarium heaters available on the market. Some are cheap and some are expensive. The best ones should cost around 20 USD. This is an amount of money you should be willing to spend to keep your Betta warm, comfortable, and healthy.

The best quality aquarium heaters do not easily fail or malfunction. So if you get a good one, it is very unlikely that it will act up and boil your pet. This should also serve as a warning if you plan to get a cheap one. You may suddenly lose a pet that you are planning to take very good care of or that you have been taking very good care of. 

To avoid changing temperatures too rapidly, some pet fish owners usually remove the fish with about a liter of water before adjusting their aquarium heaters to increase the temperature a bit. And then they put the fish with the litter of water in a clear plastic bag and float it on the new water for a couple of hours before releasing it from the bag. This practice is thought to enable aquarium fish to adapt better to temperature changes.

Dangers of the wrong temperature

If you let the temperature of your fish tank to drop below or increase beyond the ideal Betta fish temperature range, several things will happen. If the temperature is too low, your fish’s metabolism will reduce significantly. This will make it slow and very much prone to diseases. It will also make it lose its appetite. If the temperature is too high, your fish’s metabolism will increase and this will make it age faster than normal. 

Other effects of wrong temperature include freezing or boiling, shock, bloating, and/ or death. So it is very important to ensure your Betta fish lives in the right environment with the right temperature. 

You can assume that the temperature of the water in your aquarium is wrong when your fish becomes lethargic or when it starts to dart around. The best way to confirm is to get an aquarium thermometer and actually measure the water temperature. 


Betta fish are fun, colorful, and playful fish to have in a home aquarium. They are also calming, low-maintenance, and very beautiful fish pets. Although they are low-maintenance fish pets, you should take good care of them and maintain their water temperature at the ideal range (78 to 80 degrees F) or they will get weak and sick and die. If you take good care of them, Betta fish can live up to five or six years.