Betta Water Temperature: The Ideal Range & Why It Matters

If you’re wondering what the ideal water temperature for bettas is, then you’ve found the right article! In this article, not only will you find out the ideal temperature, but you’ll also learn what happens when the water becomes too hot or too cold, and most importantly, how you can keep the temperature perfect for your betta!

So keep reading to find out everything you need to know!

What Is The Ideal Water Temperature for Betta Fish? 

Fortunately, a betta’s water temperature needs are incredibly simple!

The ideal betta water temperature range between 76°F and 80°F. However, the ideal temperature you can keep your betta at is 78°F. If the temperature goes too low, it can weaken your bettas immune system, and if it goes to high it can stress their bodies.

Why Do Bettas Need This Temperature? 

Now you know the ideal temperature range for your betta fish, here’s why it’s so important!

Bettas are cold blooded fish which means that they need warm water to warm them up, unlike people who can warm themselves up. Any difference in the temperature of the water can severely affect their body temperature, consequently impairing their immune system.  

When your fish tank’s water fluctuates, or becomes too hot or too cold it’s going to be extremely stressful for bettas, and can even lead to temperature shock. A betta’s natural habitat is in the heavily planted rice paddies, swamps and shallow bodies of water in Thailand, where the tropical climate is consistently warm. which is why it’s so important to maintain the water temperature so they can be happy and healthy for as long as possible.

While you cannot recreate a completely natural environment in a bettas fish tank; water temperature is one aspect you have control over.  

blue betta

What Happens If The Water Becomes Too Hot? 

When your bettas water is too hot it will affect your betta’s metabolism, causing it to speed up. On top of this hot water contains less oxygen, making it harder for your betta to breathe.

As a result, Betta fish will start breathing rapidly or float towards the surface in search of oxygen. The heat may also cause them to start swimming erratically, and increase their metabolism as well.  (Find out other reasons bettas swim erratically.)

The high metabolism rate will stress them out, and cause them to burn through energy faster. Gradually, the haphazard symptoms will tire out the Betta fish, and a massive bout of fatigue will overcome the fish’s overall health.

And of course, a higher metabolic rate in Betta fish contributes to faster aging and a decrease in their lifespans. 

What Happens If The Water Becomes Too Cold? 

In colder water temperatures, Siamese fighting fish will experience a slowdown in their metabolism. If the temperature drops below 74°F, the cold water will cause them to become lethargic and stress their bodies out.

Since fish regulate their body temperature in accordance with their water temperature, bettas have an extremely hard time functioning in cold water temperatures.  

One of the first symptoms you’ll notice is lethargy, you’ll notice that your betta isn’t swimming around nearly as much as they used to.

Betta fish will limit their swimming to the bottom levels of the water or may not swim at all. they will seek warmth at lower water levels, and if the oxygenation in the water isn’t good enough, they may struggle to breathe.

Betta’s will also avoid eating in cold water, as their metabolism begins to slow down so much, which can lead to starvation.  

Due to a slower metabolism, your betta will also become vulnerable to bacteria, infections, and diseases such as ich, columnaris, swim bladder disease, and in rare cases dropsy. Severe infections can compromise the immune system and eventually kill the affected Betta fish. 

In severe conditions, Betta fish may slip into a life-threatening coma where you’ll need to act immediately to save them.

(Caring for your Betta can be tricky, but here’s a complete guide on how to look after them.) 

one page betta care guide infographic

Why Does the Temperature Need To Stay the Same? 

When there are fluctuations in water temperature it can cause damage to the your bettas immune system and affect their metabolism. Some of the problems that changes in a betta fish’ water temperature will produce are :

Temperature Shock

In extreme water temperatures, Betta fish will suffer from bouts of temperature shock that could lead to lethargy, coma, and possible death. 

(Find out more about temperature shock in bettas.) 

Changes in Metabolic Activity 

As Betta fish water temperature changes, the fish’s body temperature will also change. In cold temperatures, a Betta’s body will become cold, causing lethargy and a loss of appetite in your betta.

On the other hand, water temperature that is too warm can increase metabolic activity in the fish and cause the fish to become hyperactive.

Hyperactivity stresses your betta and affects their overall health and can eventually lead to energy burnout.

These sudden swings from hot too cold will eventually wreak havoc on your betta.

Respiration Problems 

As the water temperature increases or decreases, the availability of oxygen also changes. Any changes in water temperature inversely affect oxygen levels.

As previously mentioned, under hot water temperatures, oxygen levels drop dramatically, and betta fish swim to the surface in search of oxygen. The absence of oxygen will hamper their respiration process, which in turn damages the metabolic rate. 

Immune system 

The effects of changes in water temperatures will also harm your bettas immune system. Extreme water temperatures propel or even induce the birth of certain bacteria and parasites in water.

As a result, Betta fish will fall sick more often. Gradually as the strength of the immune system declines, your betta will be exposed to more and more diseases.


A weakened immune system due to changing water temperatures struggles to combat possible infections and diseases. One of the most common illnesses affecting Betta fish is Fin Rot.

This condition causes bacteria to feed upon the fins of your Betta and and if left untreated will rot their fins down to their body.

Apart from bacterial diseases, many parasites induce mild to severe infections on Betta fish. Other than external diseases and parasites, your Betta fish may also suffer from internal problems such as constipation and a loss of appetite.

betta water temperature guide

How to Maintain a Constant Temperature 

As you can see, maintaining the ideal betta temperature is vital so here are some steps you can take to ensure that betta fish stays within their temperature range.  

Use A Thermometer  

First of all, you should always keep an eye on the temperature of your tank, The best way to do this of course, is to buy a thermometer. And make sure you buy a good quality thermometer, and don’t depend solely on the aquarium or tank’s own thermostat. (This is the thermometer I use).

Use A Heater 

It’s also vital to use a heater to maintain the water temperature in your bettas tank. So invest in a good heater to ensure that it works properly and won’t break.

And you really don’t want to spare the expense when it comes to your heater because it’s easy for the water to overheat with cheap heaters.

As a rule of thumb your tank’s heater should be about 5 watts per gallon of water.

(Check out the best heaters for 5-gallon tanks. Or if you’re in a hurry I’d recommend the Fluval M Series.)

Change Water Gradually 

If you’re changing out old water for new water, make sure that the water temperature doesn’t change. An abrupt change in water temperature will induce shock in your betta. If you accidentally pour in too much hot or cold water, try to maintain the temperature by adding more water, of a similar temperature, or using devices such as a heater.

Ideally, you should try a partial water change of just 5-10% to avoid inducing a significant temperature fluctuation. 

And remember to use a water conditioner when you’re adding tap water to remove any chlorine and chloramine in it.

Keep Your Bettas Tank In An Area That Has A Stable Temperature

To avoid temperature swings, keep the tank away from the windows and doors. Making sure the temperature around your tank stays stable is one of the best ways of making sure the tank temperature itself stays stable.

betta care facebook group


Here are some frequently asked questions that people have about the perfect water temperature for their betta.

What Are The Ideal Water Parameters For A Betta Fish?

When it comes to taking care of betta fish, you’ll need to keep the water temperature between 76°F-80°F (24°C-27°C), pH level from 6.5 – 7.5, and maintain the water hardness at 4-10 dGH.

Don’t forget to keep up with regular partial water changes, too – it’s essential for your fish’s health!

Can Betta Fish Live In Room Temperature Water?

Betta fish can rarely live in room temperature water, as the temperature in rooms can fluctuate so rapidly. You should always invest in a heater to ensure that your betta is staying warm enough.

Is 70F Too Cold For Bettas?

70°F is way too cold for bettas. These tropical fish need warmth to thrive, so the colder it gets, the slower and weaker they become, which puts them in danger of infection. Keep your betta’s tank temp between 75°F and 80°F to keep them happy and healthy!

Is 24C Ok For Bettas?

Bettas do great in temperatures between 24-27°C (75-80°F), so the 24°C mark is where they’re happiest. That way, they can live a long, healthy life and stay pleasant and stress-free.

Is 84F Too Hot For Betta?

Keep the water in your betta tank on the cool side – 84°F is too warm for them. If the temperature creeps up, you’ll probably see signs of distress from your betta fish. So keep the water cool!

Why Are Temperature Changes Bad For Bettas?

Rapid temperature changes can stress out fish and cause many health issues. Fluctuations in temperature can lead to decreased appetite, a higher risk of illnesses, and even death.

Do Male And Female Bettas Need The Same Temperature?

There is no difference between a male and females bettas temperature needs. Both thrive best in temperatures as close to 78°F as possible.

How To Keep Your Betta’s Tank Warm?

Sometimes things go wrong with your tank, for example, if something goes wrong with the fish tank heater, you’ll need to know how to keep the tank warm. There are a few ways to do this.

First of all, try wrapping it in blankets to help keep the heat in. If possible place a hot water bottle in the towels to help maintain the heat even more! As well as towels you can also use blankets and tealight candles too.


Any changes in betta fish water temperatures will inadvertently affect the fish’s health. Betta fish can tolerate mild deviations from ideal temperatures, but a drastic change will pose potentially dangerous risks to their health.

Frequent and sudden fluctuation in the water temperatures will stress a Betta fish’s health. Hence, follow the steps we mentioned above to maintain your Betta fish water temperature. 


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