10 Smart Tips – Ideal Water Temperature for Betta Fish

If you love having fish for a pet, there is no doubt that you would fall for the impressive appearance of the betta fish. Looking at their vivid colors would surely relieve the stress from your daily grinds, plus, of course, keeping fish is a wonderful hobby.

However, just like any other pets, there are certain conditions that you need to fulfill your betta fish to stay alive. One of those is ensuring that the water is set at an ideal temperature.

Today, it is all about finding the right range of water temperature and how it affects the health and happiness of your betta fish.

Ideal Water Temperature for Betta Fish

The Importance of Ideal Water Temperature for Betta Fish Aquarium

The betta fish is originally from Thailand, a tropical country that has warm weather conditions. This means that the betta fish thrives well in water that has a temperature between 78 and 80 degrees Fahrenheit. Moreover, their preferred living conditions are the slow-flowing waters like rice paddies and swamps.

There are fish hobbyists who say that bettas are highly adaptable. Yes, they are but if you fail to provide them with their basic needs, do not expect them to survive long in undesirable living conditions.

If the water in the aquarium is either too hot or too cold, expect your betta fish to show weird behaviors like floating on one side of the tank. In a matter of time, don’t be surprised if you find them floating lifelessly.

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It may sound complicated but no worries because we are here to guide you in determining the ideal water temperature for your bettas. We will also touch on the correct ph level and the type of water to use so they will remain colorfully alive in their new home.

Tips on How to Set-up the Perfect and Ideal Water Temperature

1. Get the Correct Aquarium Size

It may look fancy as a home display, but those cute small bowls and vases are not the perfect fit for your betta fish. By housing them in a small container, their movements are restricted which can only shorten their lifespan.

The perfect aquarium size is the one that can hold about 5 gallons of water. If the size is below 2.5 gallons, water temperature fluctuates much faster. Plus, you might not be able to buy a fish tank water heater that can fit into a small betta housing.

But if you can get a bigger tank, the better it is for your betta fish. Larger tanks are good at maintaining the ideal water temperature.

2. The Ideal Type of Water for the Aquarium

The type of water that you pour into the fish tank has a major impact on your betta’s health. Water may all look the same (tap water, spring water, distilled, etc.) but they have different parameters.

For example, tap water is high in chlorine and could have some traces of metal that may be risky for your pet’s health. But, adding a water conditioner will remove all the undesirable contents that can harm your betta fish. Tap water minus the chlorine is ideal for your pet as it contains nutrients and minerals that are good for them.

What about bottled spring water? This one does not contain chlorine, hence, it is safe for the bettas provided that it has the right ph level (to be discussed later). Different brands contain different ph levels, so make it a habit to check the label.

Then there’s bottled distilled water. This type of water has been processed to get rid of all the chemicals, nutrients, and minerals leaving nothing but pure and unadulterated water. While distilled water is good for you, it is not advisable to use for the betta aquarium, unless you add nutrients and balance the ph level.

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So, what’s the verdict? Tap water is best used for your bettas. Using tap water will make it easier for you to mix hot and cold until the desired water temperature is achieved.

3. Choose a Good Thermometer

The best way to monitor and get accurate results is to use a good quality thermometer. Do not rely on the tank’s built-in thermostat as this may not give you the actual thermal reading.

Again, the optimal temperature range for your bettas is between 78 and 80 degrees Fahrenheit. Though they can survive a temp lower than 78 and higher than 80, it does not mean they are happy. Any temperature outside of the ideal means that your bettas are surviving but they are not thriving well.

If the water temp in the aquarium were to drop below 72 or hit above 86 degrees Fahrenheit for more than one hour, you would likely lose your bettas due to inappropriate water temperature.

Get in the habit of getting the water temperature. Doing it every day or every other day is what we recommend.

4. Choose a Good Water Tank Heater

A tank heater is one of the most important gadgets that you need to keep your pet healthy.

Bettas are adapted to warm water and the temp in your home may not be the suitable one for your pet. You see, the temp in your home is not as stable compared to the one in betta’s natural habitat. Throughout the day, the temperature in your home fluctuates depending on how warm or cool it is outside. This has a direct effect on water temperature.

This is why it is smart to use a good quality aquarium heater to maintain stable water temperature.

When choosing a water heater, take note of the following factors:

  • The heater should provide 3 to 5 watts for every gallon of water.
  • Look for an adjustable heater for more control on water temperature.
  • Should have safety features like automatic shut-off and protective casing.
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Ideal Water Temperature for Betta Fish

5. Change Water in the Aquarium Gradually

If you need to clean the tank and do a water change, be sure that the temperature of the new water that you will add to the tank is the same as the existing one.

We recommend that you do a partial water change only, about 5 to 10% to prevent inducing a sudden water temperature fluctuation.

Any abrupt fluctuations will result in shock and stress that may eventually kill your bettas. In case you accidentally added too much cold or hot water into the tank, taper the water temp by adjusting the thermostat.

When putting back the bettas into the newly cleaned fish aquarium, acclimatize them first.  They have to get used to the new water. If you temporarily housed them in a bag while doing a fish tank clean-up, allow the bag to float into the aquarium for a few hours before you set them free.

6. Keep the Ideal PH Balance

Another important issue to keep in mind is the acidity level of the water. The bettas thrive well in slightly acidic ph water level, between 6.5 and 7.5 ph.

Betta excretions and uneaten food increase the ph level of the water.

For you to determine the ph level, procure a test kit, and perform a test one to two times a week.

A lot of testing kits come with two bottles – one for increasing the ph level while the other bottle is to decrease it. This makes it convenient for fish lovers like you to adjust the ph level. Performing a ph test can save the lives of your bettas.

Be careful also when making adjustments as any sudden changes to water acidity can also shock and stress the bettas.

7. Aerate the Water

Good aeration in the aquarium is important for betta fish survival. If the water temperature in the aquarium goes up, the oxygen content in the aquarium decreases as a result of evaporation. That said, the higher you set the tank’s temperature, the more you should watch out if your bettas are getting enough oxygen or not.

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To solve the issue, you can use filters and aerating ornaments like plants to maintain the ideal water temperature for betta fish.

8. Cycle the Aquarium

If you are a newbie, cycling the tank simply means forcing the tank to undergo a proper nitrogen cycle.

The reason why you have to cycle the aquarium is for beneficial bacteria to grow to the point that they will eat the noxious compounds like ammonia and nitrites in the water.

Like everyone else, fish excretes nitrogenous products like poo and pee. These excretions break down into ammonia and nitrites which are toxic for betta fish.

You may now ask if the water temperature in the fish tank has something to do with these harmful compounds. Well, yes because the higher the water temperature is, the more toxic the ammonia is.  And, if the nitrate level increases, the ammonia level spikes, too. That’s another reason why you have to invest in a good quality thermometer and fish tank heater.

9. Feed Your Bettas With Just the Right Amount of Food

You may not be aware of it but overfeeding your betta fish can affect the quality of water in the aquarium.

Too much food equates to increased excretions. A while ago, we said that excretions are converted to harmful compounds (ammonia and nitrite) for your bettas.

10. Place the Aquarium in the Right Location

In case of extreme weather conditions, place the aquarium away from windows and doors. During colder months, you can place the aquarium near lamps and heaters.

During the summer months, avoid direct sunlight. It helps to cool down the water temp if you place it in an air-conditioned room or near an electric fan.

What Happens if Water Temperature Is Too High?

The metabolism will get affected if the water temperature is set at high. Hot water contains a lesser amount of oxygen molecules. When the aquarium heats up too much, they become abnormally active.

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As a result, you will see them breathing rapidly or floating towards the surface to get more oxygen. You’d also notice your bettas swimming erratically (swimming faster) and this increases metabolism.

A higher metabolism rate saps out their energies. If the water temperature is not corrected, fatigue will have a huge negative impact on their health, shortening their lifespan.

What Happens if Water Temperature Is Too Low?

If the water is too cold, the metabolism slows down. This means lethargy and loss of appetite to the point of starvation.

If the temperature is not corrected, the bettas are prone to contract bacterial infections. The worst scenario is that the bettas going into a coma because of cold water temperature.

The max they could survive in cold water is between 3 to 6 months.

Why Does Water Temperature Need to Be Constant?

Because in their natural habitat, they are accustomed to a steady temperature. When switching to a domesticated lifestyle, the temperature in the aquarium fluctuates depending on room and weather conditions.

These temperature fluctuations cause damage to their metabolism and immune system. Apart from the ones we mentioned earlier, here are some of the health problems that can occur as a result of inappropriate water temperature:

  • Temperature shocks that lead to lethargy, coma, and death
  • The compromised immune system may cause fin rot. This is a condition wherein the bacteria feeds on the fins of the bettas and slowly eat up the whole body
  • Respiration problem


Like any other pets, the bettas are a wonderful and colorful addition to your home. They may not be as demanding but they also need care and attention. Since they thrive in a tropical environment, the water temperature in their aquarium is an important issue for their happiness and longevity.

A sudden change in water temperature affects their health. Yes, they can adapt to mild deviations but a drastic change poses danger to their system. If you will follow the 10 smart tips we have outlined for you, your bettas can add color to your life longer.

10 tips on setting the ideal water temperature for betta fish tank.

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