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The 4 Best Betta Fish Tank Heaters

Betta fish are tropical fish that require tank heaters to keep the water temperature acceptable and consistent. Room temperature water is almost never warm or steady enough to suit their demands.

Choosing the correct heater for your Betta's tank is critical to ensuring that the temperature remains safe and comfortable for your Betta fish.

Whatever the size of your Betta's tank, there is a heater to suit your demands. A heater that is too powerful will kill your fish, while a heater that is too weak can cause disease, so selecting the proper heater can help keep your Betta safe.

Here are BestForPets' (bestforpets.org) reviews of the best betta fish tank heaters, regardless of size.


Fluval 50-Watt Submersible Glass Aquarium Heater – Ideal for 10-Gallon Tank

The Fluval Submersible Glass Aquarium Heater 50-Watt is the best choice for your 10-gallon Betta aquarium. This heater has a capacity of 15 gallons and is precise to 1 degree.

It is protected with shock-resistant borosilicate glass, which reduces the chance of cracking even when bumped. Suction cups hold it to the interior of the tank.

With an adjustable temperature range of 18 degrees, you can find the ideal temperature for your Betta fish. It has a unique reflective coating that helps to disguise the heater within your tank, making it almost invisible.

At 11 inches tall, this heater may be too big for some 10-gallon tanks. The heater has a fill line mark on it, and the water must at least reach this level to keep the heater from breaking.


  • Heats tanks up to 15 gallons in size.
  • 18-degree temperature range
  • Within 1 degree of accuracy
  • Shock-resistant shell
  • Suction cup attachments are provided.
  • The reflective casing aids in the concealment of the heater.


  • Some 10-gallon tanks may be too tall for it.
  • To keep the line from breaking, it must be filled with water at least halfway.


Electronic Cobalt Aquatics

The Cobalt Aquatics Electronic Neo-Therm Submersible Aquarium Warmer is the ideal heater for a 5-gallon Betta tank. This little heater has a temperature range of 30 degrees and can heat tanks up to 6 gallons.

It offers a one-touch setup and a shatterproof casing that prevents fracture if bumped. Suction cups hold it to the interior of the tank.

This thermometer is precise to 0.5 degrees, making it an excellent choice for keeping your Betta fish safe. It also returns to the previously set temperature when powered back on after a power interruption.

It has an LED display that shows the specified temperature as well as the current tank temperature. It also features a built-in thermal protection circuit that forces the heater to shut down if it detects that it is overheating.

Despite its modest size, this heater is dark and conspicuous, especially in a small tank. To prevent the heater from cracking, the bottom of the heater should constantly be immersed.


  • Heats tanks up to 6 gallons in size.
  • 30°C temperature range
  • Precision to within 1
  • Case with shatterproof glass
  • Suction cup attachments are provided.
  • After a power loss, it returns to its former temperature.
  • The LED display shows the current and specified temperatures.
  • Thermal protection circuit built in


  • In a tiny tank, black is obvious.
  • At all times, the bottom must be immersed.


Submersible Aquarium Heater for Marina Betta

The Marina Betta Submersible Aquarium Heater, which is designed to heat aquariums 0.5-1.5 gallons, is the finest heater for your 1-gallon Betta tank.

It is adjusted to around 78 degrees Fahrenheit to keep your Betta’s tank at the ideal temperature. It’s made of tough polymer and employs suction cups to stay attached to the tank.

Because this heater is completely submersible, you may place it almost anyplace in your little Betta tank. Following a power interruption, it will automatically restart and continue warming to the pre-set temperature.

Because this heater has a fixed temperature that cannot be changed, it is advisable to purchase a thermometer to verify that the water temperature remains within a safe range. It’s covered in a black housing, which makes it stand out, especially in a tiny tank.


  • Heats tanks up to 1.5 gallons in size.
  • Betta fish should be kept at 78 degrees.
  • Polymer casing that is long-lasting
  • Suction cup for attaching to tank is included.
  • Because it is fully submersible, it may be placed anywhere in the tank.
  • After a power outage, it automatically restarts.


  • The temperature cannot be changed.
  • A thermometer must be purchased separately.
  • In a tiny tank, black is obvious.


Aquarium Heater Eheim Jager Thermostat

For tanks larger than 10 gallons, the Eheim Jager Thermocontrol Aquarium Heater is the finest option.

This heater is available in seven sizes ranging from 100 to 300 watts, which means it can heat tanks up to 264 gallons. The 75-watt type, which warms tanks ranging from 15 to 26 gallons, is ideal for a big Betta tank.

It’s adjustable from 68 to 90 degrees F, accurate to 0.9 degrees, and attaches to the tank with twin suction cups. This heater is enclosed in special lab glass, which aids in maintaining constant temperature levels in the tank.

It has a dry run shut-off so that if the water level drops too low, the heater will turn off before the glass breaks.

Because the shell is not reflective, the heater may be visible in your tank. It may also be too tall in shorter tanks, forcing you to position it at an angle, making it more visible.


  • Can heat tanks up to 264 gallons in size.
  • 22-degree temperature range
  • Within 0.9 degrees of accuracy
  • Suction cups are included.
  • The case is comprised of a unique glass that helps to keep the temperature stable.
  • Mode of dry run shutdown


  • This might be evident in your aquarium.
  • Smaller aquariums may find it too tall.
  • Choosing the Best Betta Fish Tank Heaters: A Buyer’s Guide


There is a heater for every size Betta tank to keep your Betta fish safe and comfortable. The Marina Betta Submersible Aquarium Heater is the finest choice for 1-gallon aquariums because it is designed for tanks 1.5 gallons and less.

The Cobalt Aquatics Electronic Neo-Therm Submersible Aquarium Heater is the finest option for a 5-gallon tank, and the Fluval Submersible Glass Aquarium Heater 50-Watt is the best option for a 10-gallon tank.

You may begin your search for the best betta fish tank heaters by reading BestForPets‘ (bestfprpets.org) reviews. Finding the perfect heater does not have to be a difficult effort, but it is essential to select a heater with excellent functionality and safety features that will provide optimum water heating and safety for your Betta fish.


What can I do to keep my betta fish warm?

An aquarium heater is the greatest method to keep a Betta warm. These heaters come in a variety of forms and designs and are quite efficient at warming up your tank and maintaining a consistent temperature. However, for the greatest results, pick a gadget that fits your tank configuration.

Is a heater beneficial to betta?

Yes, because Bettas are frequently found in tropical environments, a heater is essential. As a result, the fish have become acclimated to higher temperatures, which normally necessitate the use of an aquarium heater to sustain.

However, because of their tropical origins, these fish are also extremely resistant to temperature variations.

Is it possible for betta fish to be burnt by a heater?

Yes, aquarium heaters can burn Betta fish, albeit this is not a typical occurrence. This is usually caused by the fish getting too close to your heater and does not result in significant burns.

To avoid such burns, make sure your heater is not in a central area and has some form of covering.

How do aquarium heaters function?

Aquarium heaters function by combining energy with metals that can be heated. The steady heating of the interior metal heats the gadget and, as a result, the surrounding water in your tank. This should be repeated until the water is equally heated and safe for your fish to swim in.

Why is my fish congregating around the heater?

The most typical cause for your fish remaining near the heater is uneven or poor heating of the water in your tank.

It can be caused by a number of factors, including a defective heater or incorrect placement of your aquarium heater in your tank. To resolve this, move your heater to a new position or use a different one.

What temperature is ideal for a fish tank?

Most fish species can thrive happily and comfortably at temperatures ranging from 75 to 80 degrees Fahrenheit.

While there is no ‘optimal’ temperature for fish tanks because each plant and fish species has distinct needs, there are some general suggestions you may follow. Before choosing on a temperature, be sure to consider your dogs’ needs.

How should I position my aquarium heater?

Your aquarium heater should be placed near moving water. It might be next to the filter or an air pump that circulates water around the tank. Keeping your heater here is advantageous since it allows hot water to spread and evenly heat your tank.

Buyer's Guide

Why Is a Heater Important in Your Betta’s Tank?

Betta fish are tropical fish that must be kept in warm water. They can survive in temperatures ranging from 72 to 82 degrees Fahrenheit, but they flourish in temperatures ranging from 78 to 80 degrees Fahrenheit.

One of the most crucial features of your Betta’s tank temperature is not simply the temperature itself, but its stability. If the temperature is constantly shifting within a 10 degree range, your Betta will get anxious and prone to sickness.

Rapid temperature swings can also produce temperature shock, which can be fatal. Choosing a practical and dependable heater will assist you in maintaining a steady and safe temperature in your Betta fish tank.


Select a heater that is suitable for the size of your Betta’s tank. Choosing a heater with a wattage that is too high for the demands of your tank might cause fast temperature changes and overheating, which can kill your Betta fish.

If you pick a heater with insufficient wattage, you will experience the opposite problem. Bettas that are maintained in excessively cold water become prone to sickness.

Tank Design

When selecting a heater and deciding where to install it, keep the form of your tank in mind. If your Betta is in a 3 foot long tank, placing a heater at one end of the tank may result in uneven heating of the water.

You’ll want to place your heater in a slightly central spot in your tank to guarantee that the water is heated uniformly throughout.


Some warmers have features such as LED displays and built-in thermometers, which may help you monitor your tank more carefully.

Some heaters are relatively basic and lack particular features, while others do not even allow for temperature changes. Selecting the qualities that are important to you might help you choose a heater.

Author Image

Dr. Deborah Fletcher

Deborah R. Fletcher, DVM, is a skilled veterinarian with more than 15 years of experience dealing with companion and exotic animals. She has experience caring for a variety of animals, including household cats and dogs, reptiles, birds of prey, and even primates. Dr. Fletcher is a valuable part of the BestForPets team, where she contributes to their aim of providing pets and their owners with the finest possible treatment and services.

Veterinarian (DVM) Dr. Deborah Fletcher


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