Do Betta Fish Need A Heater? (finally answered!)

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A recent survey found Betta fish to be one of the most widely kept fish in the US, and it is easy to see why. Betta fish are colorful, personable, and easy to care for. They are often one of the first fish new fish keepers own.

When I give Betta fish keeping and breeding talks at shows and clubs around the country there is one question that comes up time and time again, ‘Do Betta fish need a heater?’.

Yes, Betta fish do require a heater. Betta fish are a tropical species of fish as they come from warm parts of Southeast Asia. Betta fish need their aquarium water to be kept at around 75°F to 82°F (24°C – 28°C). Adding a submersible aquarium heater is the easiest way to keep a Bettas tank at a constant temperature.

Do Betta Fish Need A Heater?

Betta fish originate from Southeast Asia and natively live in areas including Thailand, Cambodia, and Southern Vietnam. These parts of the world are naturally warm as are the waterways.

Many Betta keepers are not aware that their Bettas require warm water and so keep them without a heater.

Betta fish have evolved to live in warm water and as such, Bettas do require a heater in their aquariums. Betta fish kept in aquariums without a heater are often susceptible to diseases brought on by the stress of not being warm enough.

What is the Ideal Temperature for Betta Fish?

Betta fish need to be kept at a constant temperature of around 75°F to 82°F (24°C – 28°C). They can tolerate temperatures outside of this range for very short periods of time, but if they are kept either colder or warmer than this temperature range for too long their health will deteriorate.

What is the Minimum Temperature for Betta Fish?

The minimum temperature I would ever like to see a Betta fish at is 70°F (21°C).

Betta fish can tolerate temperatures slightly lower than their optimal range, but only for short periods of time. If Bettas are kept at temperatures that are too low, they can struggle to digest and metabolize their food. Food can even sit and rot inside the Bettas body.

Unfortunately, many people keep their Bettas in very small bowls or vases. These containers are often too small to include an aquarium heater, so people don’t put one in.

Ironically, very small bodies of water can be affected by vast temperature swings. On warm days the bowls heat up quickly. Conversely, on cold nights the temperature plummets just as quickly. Adding an aquarium heater would help stabilize the water temperature and keep the Betta happier.

What is the Maximum Temperature for Betta Fish?

Just as Betta fish have a minimum temperature they should be kept at, they also have a maximum temperature. When Betta fish are kept in water that is too warm their metabolism can race, meaning they need to eat large quantities of food to keep up.

The maximum temperature a Betta fish should be kept at is 83°F (28°C).

Care should be taken to ensure a small Betta tank is not kept in direct sunlight. Natural sunlight streaming through a window can quickly increase the temperature of a small Betta tank or bowl. There have been reports of Betta fish literally cooking in their bowls which were left in direct sunlight on a sunny day.

What is the Best Heater for a Betta Fish?

When deciding which heater is best for a Betta, the key question is what size tank is the Betta being housed in. There are many different aquarium heaters on the market and many of these cater to very small tanks. My list below looks at the best heaters I have found for my Bettas.

10w YukiHalu USB Powered Submersible Aquarium Heater

I have used this tiny heater to great effect over the last couple of years. I have a couple of very small tanks, and this 10w heater does the job perfectly.

The temperature can be set between 64°F and 93°F and is said to be accurate to 1°F.

Another feature this heater has which is especially important in very small tanks is overheating protection. If the heater begins to overheat the power will be cut off automatically preventing your Betta from cooking.

PULACO 25W Small Aquarium Betta Heater

This is another heater I have in a number of my aquariums. At 25w this heater is great for aquariums which are around 5-gallons (19 liters).

This heater is preset at 78°F (25.5°C) which is an ideal temperature for a Betta fish. It has an accuracy of +/- 3°F which keeps the water temperature right where it should be.

Another benefit I have found to this little heater is the size. At only 4.9″ it is essentially made for small tanks.

FREESEA Aquarium Fish Tank Heater

The main reason I love using this heater in my Betta tanks is that the temperature can be adjusted using the controller that sits outside the tank.

This heater can be adjusted between 63°F to 94°F (15°C to 34°C) making it suitable not only for Bettas but for just about every fish in the hobby.

The manufacturer had rated this heater as suitable for use in tanks up to 50-gallons (189 liters), which should cover just about every Betta tank anyone is using.

In Conclusion

Bettas are tropical fish that need to be kept in warm water. Keeping them in water that is too cold leaves them susceptible to pests and diseases. Keeping Bettas too cold can also lead to stress, and stress kills Bettas very quickly.

I would strongly advise anyone keeping or thinking of keeping a Betta to make sure their aquarium has a heater, no matter how small the aquarium is.

About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James

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