Best Aquarium Heaters (For Every Sized Tank)

Aquarium heaters are essential for any fish tank. They keep the water at a consistent temperature, which is important for your fish’s health and well-being. However, choosing the right aquarium heater can be challenging, especially if you’re a beginner. 

So, in this article, we’ll discuss everything you need to know about the best aquarium heaters and some of the best products out there. So, keep reading! 

Do You Need An Aquarium Heater?

It’s always best to have an aquarium heater in your tank. Even if you have cold water fish, it’s still vital to keep the water temperature stable as fluctuations can affect your fish and even kill them!

Keeps the Water at a Consistent Temperature

Fish are cold-blooded animals, which means their body temperature is affected by the temperature of their environment. If the water temperature in your tank is too cold, your fish will become sluggish and may eventually die.

Prevents Fish Diseases

Some fish diseases are more likely to occur in cold water. For example, ich is a common fish disease that’s caused by a parasite that thrives in cold water. An aquarium heater can help to prevent ich by keeping the water temperature in your tank at a warm, comfortable level for your fish.

Promotes Breeding

Some fish, such as guppies and mollies, will only breed in warm water. If you want to breed your fish, you need an aquarium heater to keep the water at the right temperature.

If you have fish that can survive in cold water, such as bettas and catfish, you may not need an aquarium heater. However, it’s always a good idea to have one on hand in case the water temperature in your tank drops unexpectedly.

What Wattage Should Your Aquarium Heater Be?

When choosing an aquarium heater, a good rule of thumb is to use 5 watts per gallon for smaller aquariums up to 55 gallons, and 3 watts per gallon for larger tanks over 60 gallons. 

If your aquarium is in a very cold room or placed near a chilly exterior wall or outside door, consider using a larger heater or adding a second one. This helps ensure that your fish and other pets in your aquarium stay comfortable and healthy.

Selecting the right wattage is essential to prevent temperature imbalances in your aquarium. If the heater is not powerful enough, it may struggle to maintain the right temperature, causing stress to the fish and harm their health. 

On the other hand, an overly powerful heater can heat the water too quickly, risking overheating and damage to the aquarium’s ecosystem. Always check the product specifications and recommendations from the heater manufacturer, as different models may have varying guidelines.

How Do You Choose An Aquarium Heater For Your Tank?

When choosing an aquarium heater for your tank, there are some important factors to consider. Choosing the right heater ensures your fish stay comfortable and healthy in their environment.

So, here’s a simple guide to help you make the right decision:

1. Calculate Wattage

A common rule of thumb is to use 5 watts per gallon for tanks up to 55 gallons and 3 watts per gallon for larger tanks over 60 gallons. This ensures the heater can efficiently heat the water.

2. Consider Tank Size

The size of your aquarium matters. Larger tanks need higher wattage heaters to maintain the desired temperature effectively.

3. Adjustable Temperature

Choose a heater with adjustable temperature settings so you can set the ideal temperature for your fish species.

4. Type of Heater

Choose the type of heater that fits well with your tank setup, such as submersible, hang-on, or in-line heaters.

5. Safety Features

Look for heaters with safety features like automatic shut-off to prevent overheating accidents.

Best Aquarium Heaters For Small Tanks (5-10 Gallons)

With so many different aquarium heaters on the market, it can be difficult to choose the best one for your tank. So, we’ve compiled the best aquarium heaters voted most popular by fishkeepers for your convenience!

Aqueon Pro Submersible Heater

The Aqueon Pro Submersible Heater is designed to keep aquarium water at a consistent and optimal temperature, ensuring your aquatic inhabitants thrive. It features a durable shatterproof construction, making it safe for use in small tanks.

This heater is fully submersible and can be easily installed with the adjustable suction cups, providing a sleek appearance within your aquarium. Also, its precision temperature control allows for accurate adjustments, ensuring your aquatic pets are kept comfortable and stress-free.


  • Easy to install and set up.
  • Provides consistent heating performance.
  • Sturdy build quality for long-lasting use.
  • Submersible design takes up minimal space in the tank.
  • Precise temperature adjustments for the comfort of your aquatic pets.


  • Sometimes the suction cups can lose grip over time.
  • The temperature dial might be too sensitive, requiring careful adjustments.
Aqueon Adjustable PRO Aquarium Heater Up to 20 Gallons, 50 Watts
  • Adjustable heat setting 68 to 88°F, Electronic Thermostat accurate to +/- 1°

Cobalt Aquatics Neo Therm Heater

The Cobalt Aquatics Neo Therm Heater is a compact and reliable heating solution for small aquariums. Its slim design allows for easy placement, and the one-touch control system makes it simple to set and adjust the temperature. 

The LED indicator provides a clear indicator of the current temperature, so you can monitor it at a glance. Also, the heater’s electronically controlled thermostat ensures accurate and consistent heating performance, keeping your aquatic environment stable.


  • Easy to operate with simple temperature settings.
  • Space-saving design ideal for smaller tanks.
  • LED indicator allows for quick temperature checks.
  • Reliable and efficient heating performance.
  • Compatible with various types of aquatic environments.


  • Some people have said that the temperature display is slightly inaccurate.
  • The heater’s casing may get hot during operation, which requires cautious handling.
Cobalt Aquatics Neo-Therm Pro Aquarium Heater, Made in Europe, Fish Tank Heater for Freshwater or Saltwater Tanks, Turtle Tank Heater, Submersible, Auto Shutoff, Temperature Controller Thermostat 50W
  • MADE IN EUROPE with place anywhere suction cups and reversible mounting bracket. This heater for fish tank works as a fish heater, turtle heater, or mini aquarium heater.

Eheim Jager Aquarium Thermostat Heater

The Eheim Jager Aquarium Thermostat Heater is a popular choice among aquarium enthusiasts for its reliability and precision. It features a TruTemp dial that allows for precise temperature adjustments, ensuring your aquatic pets are kept in their preferred temperature range. 

The Thermo safety control feature prevents overheating, providing an extra layer of safety for your tank’s inhabitants. The heater is fully submersible and easy to install with the included mounting bracket.


  • Reliable and stable temperature control.
  • Easy to install and adjust.
  • Durable build for long-lasting use.
  • Provides even heating throughout the tank.
  • Safety features for worry-free operation.


  • If you are just starting out, the heater can take longer to stabilize the temperature.
  • The design of the temperature dial could be improved for easier reading.

Best Aquarium Heaters For Small-Medium Sized Tanks (11-20 Gallons)

When it comes to maintaining the ideal environment for your beloved fish in small to medium-sized tanks, a reliable aquarium heater is a must-have. So, here are our handpicked selection of top-rated heaters for tanks ranging from 11 to 20 gallons.

Hygger 100 Watt Mini Submersible Heater

The Hygger 100 Watt Mini Submersible Heater is designed to provide precise and consistent heating for small to medium-sized aquariums. This compact heater is fully submersible and easy to install with adjustable suction cups, making it convenient to position and hide in the tank. 

The built-in external controller allows for easy temperature adjustments, ensuring your aquatic inhabitants stay comfortable. The heater also features an auto shut-off function when it reaches the desired temperature, preventing overheating.


  • Easy to install and set up with adjustable suction cups.
  • Provides consistent and reliable heating performance.
  • Compact design that doesn’t take up much space in the tank.
  • External controller allows for convenient temperature changes.
  • Safety features prevent overheating and potential damage to the tank.


  • Sometimes the temperature reading isn’t as accurate on the heater.
  • The external controller may require extra care to avoid water damage.
Hygger 100W Mini Submersible Digital Display Aquarium Heater for Small Fish Tank, Compact and Fast Heating Thermostat, with External Controller and Built-in Thermometer, for Betta, Turtle
  • 🐠【Compact Small Heater】110-120V/60HZ oval shape design little aquarium heater, fast heating for small fish tank. 50W tank heater is for 1-6.5gallon, 100W tank heater is for 6.5-13 gallon. Heater Dimension: 2.7×1.4x 4.5 inch. The power cord is 5ft, long enough for use indoors. With 2 strong suction cups at the back side of the betta heater, it’s easy to install it on to glass, acrylic or plastic tank

Marineland Precision Heater

The Marineland Precision Heater is another popular choice for small to medium-sized aquariums. It offers a wide temperature range and maintains the desired setting with minimal fluctuations. 

The shatterproof construction ensures durability and safety, and the heater is fully submersible for easy installation. The integrated thermal switch provides automatic shut-off to prevent overheating. The Marineland Precision Heater is designed to deliver reliable and consistent performance.


  • Provides stable and accurate temperature control.
  • Sturdy and durable construction.
  • Easy to install and maintain.
  • Wide temperature range for various aquatic species.
  • Automatic shut-off feature for peace of mind.


  • Again, the temperature accuracy over time becomes less accurate.
  • The temperature dial might be too sensitive, requiring careful adjustments.
Marineland Precision Heater for Saltwater or Freshwater Aquariums
  • This 300 watt heater is for aquariums up to 80 gallons. Adjustable temperature dial allows you to set the temperature 1 degree with every click.

Best Aquarium Heaters For Medium-Large Sized Tanks (20-50 Gallons)

Having the right heater for your medium to large aquarium is absolutely important to create the most suitable and comfortable home for your fish. So, here are some of the best aquarium heaters on the market to help you pick the best one for your needs!

Hygger 200watt Digital Quartz Aquarium Heater

The Hygger 200 watt Digital Quartz Aquarium Heater is designed to provide precise and stable heating for medium to large-sized aquariums. This heater uses advanced technology to ensure accurate temperature control, and the built-in external controller makes it easy to adjust and set the desired temperature. 

The heater is constructed with high-quality quartz glass, which is shatter-resistant and provides even heat distribution. The auto shut-off feature provides an extra layer of safety, turning off the heater when the desired temperature is reached.


  • Provides accurate and consistent temperature regulation.
  • Sturdy and shatter-resistant quartz glass design.
  • Easy to install and use with external controller.
  • Suitable for medium to large-sized tanks.
  • Auto shut-off for added safety.


  • The external controllers display may not be accurate in some cases
  • The temperature dial may require calibration for precise adjustments.
hygger 200W Aquarium Heater, Ultra Short Quartz Fish Tank Heater with LED Digital Display Thermostat Controller for 20-52 Gallon Freshwater Saltwater Tank
  • 【Explosion-proof and anti-corrosion aquarium heater】Heating rod heating body is made of explosion-proof quartz glass, nickel-chromium heating wire and silicon carbide heat-conducting material, and the fish heater shield is made of high-temperature resistant ABS material. Manufactured into a tank heater that is anti-corrosion, non-leakage, non-conductive, explosion-proof, and makes water heating faster.

Fluval M200 Submersible Heater

The Fluval M200 Submersible Heater is another popular choice for medium to large aquariums. It features a sleek and compact design that allows for discreet placement in the tank. The Vuetech LCD display offers real-time temperature readings, and the heater can be easily adjusted with the dual temperature control buttons. 

The integrated fish guard prevents direct contact between the heater and your aquatic pets, ensuring their safety. The Fluval M200 is designed for easy installation and reliable performance.


  • Provides accurate and stable temperature control.
  • Easy-to-read LCD display for quick temperature checks.
  • Dual temperature control buttons for convenient adjustments.
  • Fish guard prevents accidental contact with the heater.
  • Easy to install and maintain.


  • The design of the LCD display could be improved for better visibility.
Fluval M 200 Watt Submersible Heater
  • Submersible heater provides exceptional performance and unsurpassed reliability


Here are some frequently asked questions that people have when they’re buying a heater for their fish tank!

How Often Should You Replace Your Heater?

Most aquarium heaters have a lifespan of around 3 to 5 years. It is recommended to replace your aquarium heater every 2-3 years to ensure its efficiency and safety. If your aquarium heater is past its prime or showing signs of malfunction, it’s better to replace it early rather than waiting for it to stop working. 


Choosing the best aquarium heater for your tank can be a daunting task, but it’s important to do your research and choose a heater that is the right size and power for your tank. By following the tips in this article, you can be sure to find the perfect aquarium heater to keep your fish healthy and happy.

About the author

Hey! I'm Antonio!

Betta fish keeper for over 6 years now! Since owning a betta I've also housed all kinds of tropical fish, and have seen all manner of problems and how to look after them!

If you need any advice you can always message me or better yet join the Facebook group where a community can answer your questions!

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