What’s the Best Temperature for Betta Fish?

Last Updated on December 1, 2022

Betta fish, or the siamese fighting fish, are a popular freshwater fish known for their bright and vibrant colors. They belong to the list of sea creatures people like to keep in their home aquariums.

Bettas may be known to be low-maintenance fish, but that’s not truly the case. They are not starter fish; if you want to own one, being equipped with proper knowledge is crucial.

In this article, we will discuss what ambient temperature best suits your betta fish to keep them healthy.


  • The best betta water temp range from 78°F to 80°F (25-27°C).
  • Choosing the right tank size, using a heater and thermometer, and keeping a suitable pH level are the best ways to keep your betta healthy.
  • Too much heat or cold can be dangerous for betta and lead to diseases and other health problems.
  • There are some alternatives to keeping your betta fish warm without a heater, but they are not as convenient.
  • Temperature shock happens when fish experience a sudden temperature change.

What’s the ideal water temperature for your Siamese fighting fish?

The ideal temperature for betta fish water is between 25-27ºC or 78-80ºF.

Wild bettas usually live in rice paddies, swamps, or ponds where temperatures are inconsistent.

Wild betta fish blue and grey color
Image from Canva.com

They also survive in a tropical climate, so they can thrive in temperatures outside this range.

But, if you’re keeping this tropical fish as a pet, knowing the best water temperature should be a top priority to prevent illnesses.

It’ll also help avoid unnecessary stress on your betta just because you’re unaware of the right temperature for them to thrive.

If you notice your betta fish is lethargic, unresponsive, or staying at the bottom of the tank, ensure that you check the water temperature, as it may be the culprit.

Exposure to freezing and hot water can cause illness and may eventually lead to the death of your betta fish.

So remember that keeping a betta fish as a pet comes with responsibilities. It’s not only the costs of equipment or tools but also the proper care and attention the betta needs to stay healthy.

How to keep the perfect betta fish water temperature?

Fortunately, it’s easy to keep the ideal temperature for your betta. Just follow the steps below to keep your fish healthy:

1. Choose the right betta fish aquarium or tank size

Choose the right fish tank size

Your betta fish tank size should not be smaller than 2.5 gallons. Ideally, the larger, the better, so it’s best to get five gallons or more.

The main reason why smaller tanks are not recommended for betta fish is that the water temperature can fluctuate more quickly.

Also, adding a heater to an already small betta fish tank is not a good idea, as it can only harm your fish.

In contrast, the temperature in larger tanks is easier to regulate and maintain.

If you’re thinking of putting your betta in a fishbowl or vase, you may need to rethink having a betta fish as a pet overall.

2. Get a heater for your betta’s tank

The average room temperature is 68-72°F, and your betta needs 78-80°F. Unless you live in a hot room, you must get an aquarium heater.

A tank heater is the easiest way to maintain the betta fish water temperature. But you need to research and consider your tank size before buying one.

For example, a common rule of thumb for aquarium heaters is five watts per gallon for smaller aquariums (55 gallons or less) and three watts per gallon for larger ones (over 60 gallons).

If possible, add a little more to your budget and buy a reliable and sturdy one to avoid future headaches.

However, if you don’t have the budget to buy one yet, you can still do so even without one. It’s not as convenient as an aquarium heater, but it should do for now.

3. Buy a thermometer

best temperature for betta fish
Image from Canva.com

You’ll need to check your betta fish water temperature often to be sure it doesn’t go above or below the ideal range.

Although some heaters have a thermostat, it’s better to keep a separate aquarium thermometer to be sure you’re getting accurate measurements and maintaining the ideal betta temperature.

You can get a digital or analog thermometer to attach to the tank’s side. Either way, having one will help you easily monitor the water temp.

4. Keep the ideal pH level of your betta tank water

Image from Canva.com

Maintaining the proper pH level is also crucial for betta fish water temperature.

The ideal pH level is between 6 and 8, but it should lean towards the slightly acidic side (6.0-7.5). For bettas, having acidic to neutral water yields better results in keeping them healthy.

But, you should avoid using harsh chemicals to adjust the pH level of your tank because this can bleach the fish’s skin and damage their gills.

If your tank’s pH falls below this range, your betta fish will likely suffer from health problems such as stunted growth, reduced appetite, and possible death.

To maintain an ideal pH level in your tank, ensure the water is always fresh and change it at least once a week.

How to keep a betta fish water temp warm without a heater?

Not everyone has the budget or time to buy a betta tank heater. Fortunately, there are methods you can use to keep your betta warm without one:

1. Use a fluorescent light – Fluorescent light is suitable for betta as it doesn’t emit too much heat, so it can gradually increase at the right temperature. You can add one or two of these in your fish tank to encourage plant growth.

Image from Canva.com

2. Place the fish tank within natural sunlight – Direct sunlight can heat the water to a comfortable range and also helps maintain the growth of live plants. But it can also encourage algae growth. Also, depending on the weather or how hot the sun is, it can make the water too hot for bettas. This can cause betta to experience shock or even death.

3. Keep the bettas in a warm area of the house – If you have a garage, shed, or a place warmer than the standard room temperature, you can temporarily place your betta there.

Keep in mind that these are temporary solutions, as a betta may not be comfortable being in direct sunlight, constantly having a bright light in its tank, or being kept in a room with no light.

Be sure to get a heater as soon as possible to keep a regulated temperature for this tropical fish.

4. Use a hot water bottle – This can be an alternative to a heater. Still, I don’t recommend it because bettas are sensitive to temperature changes, and having a hot water bottle can cause sudden fluctuations.

If you have no choice, you can do this for short periods and carefully monitor the water temperature, as bettas can get sick or even die if the temperature is too high.

What happens if your betta water is too hot?

A high water temperature is dangerous and will lead to a faster metabolism, shortening their lifespan. You may notice your betta fish rapidly swimming or have unusual swimming patterns in hot water.

85°F is on the high end, so anything higher than that has detrimental effects, especially for prolonged exposure.

They may thrive in this water condition, but it’s very uncomfortable for them, and their quality of life will significantly decrease.

What happens if your betta water is too cold?

Cold water temperatures may bring your betta fish’s metabolism slower, make them lethargic, and cause their immune system to deteriorate.

Betta fish can live in cold water for about 3-6 months. But depending on how cold the water is, it will certainly affect and shorten their lifespan.

So if the cold temperatures go down to the lower end of the betta water temperature range, you should consider using a heater to keep your betta comfortable.

What is temperature shock?

This happens to a betta fish when it’s suddenly transferred from one temperature to another.

While slight temperature changes are tolerable, bettas are still sensitive to unexpected temperature changes, especially extreme differences in temperature level.

This usually happens if you clean the tank and do not do the proper acclimation steps or if the heater is not functioning well.

Letting your betta fish get used to its water temperature may be slow and tedious, but it will give your betta a chance to thrive.


Bettas are an excellent addition to your home and are very beautiful to look at. But before you commit to getting one, ensure you understand that betta fish are sensitive to water temperature.

If you already have one, do your job as a fish owner. Invest in good equipment and maintain the best betta fish temperature and living environment so they can survive and have a long and healthy life.


How warm should my water be for my betta fish?

Your betta fish temperature range should be from 76°F to 85°F (24-29°C). Anything above 85°F is dangerous.

What temp should betta water fish be?

The best water temperature for this tropical fish is still 78-80ºF (25-27ºC).

Is 70ºF too cold for a betta?

Yes. Do your best to achieve a temperature of 76°F (24°C). Anything below that is too cold, and betta fish can suffer from health problems.