Keep Your Fish Alive With The Best Aquarium Heater

Keep Your Fish Alive With The Best Aquarium Heater

For many people, fish are the only type of pets they can have. While you may not be able to cuddle with them or tuck them into a comfortable bed, attaching the best aquarium heater to their tank to warm up the water.

In this guide, we are going to provide you with five reviews to help you find the best heater for aquariums. If you still want to keep shopping around, we also want to provide you with features you’ll want to take into consideration when you’re trying to figure out what is the best aquarium heater.

Best Aquarium Heater

Let's take a look on our top recommendations for the best aquarium heater on the market.

Winner: Aqueon Pro Aquarium Heater

The Aqueon Pro Aquarium Heater is a heater that you can fully submerse in your tank. This model is available in several different wattages, so you can trust you will find the perfect wattage for your specific tank. Notable features of the Aqueon Pro Aquarium Heater include:

  • Adjustable heat setting 68 to 88°F, Electronic Thermostat accurate to +/- 1°
  • plus-circle
    Shatterproof and nearly indestructible
  • Fully submersible; Auto Shut-Off when over-heats, resets when it cools down
  • LED light is always on: red when heating, green when not heating
  • plus-circle
    Limited Lifetime warranty

If you’re concerned about the dimensions of your tank, this heater can be placed both vertically or horizontally. The heater is held in the desired position with secure suction cups.

The core of the heater is made from durable aluminum and the outside is coated in a durable thermal plastic material. This material distributes the heat evenly, but more important, is shatterproof and nearly indestructible.

For your convenience, the heater features a two-indicator light to let you know when the heater is on (it will glow red) and when it has reached the desired temperature (it will glow green). You can adjust the heat via the dial on the top of the heater. Temperature accuracy with this heater is within 1 degree.

Aqueon Pro Aquarium Heater



When looking at what people had to say about the Aqueon Pro Aquarium Heater, they had great things to say. People were impressed by how responsive the customer service is. A few people have commented they had the product for three or four years and when it stopped working properly, the company honored their lifetime warranty and sent out a replacement very quickly.

Others commented they liked how quickly the heater is capable of heating up their tank. They went on to say the auto-off switch and temperature detection features were a great addition.

Of the critical reviews, several customers reported the heater cracked (or shattered), despite the products claim of being shatterproof. These customers reported the broken heater leaked toxins into the tank, thus killing all of their fish. Of the less tragic reviews, people were upset that the unit was not capable of maintaining temperature and it was off by as much as 5 degrees.

Runner Up: Tetra Submersible Aquarium Heater

The Tetra Submersible Aquarium Heater is a heater that does not require adjustments because it maintains a steady 78 degrees Fahrenheit at all times, thanks to the built in electronic thermostat. Notable features of the Tetra Submersible Aquarium Heater include:

  • Heater includes indicator light to let you know when heater is on
  • plus-circle
    Light will be red when heating and green when the proper temperature has been reached
  • Built in electronic thermostat to automatically maintain water at 78° F
  • Ideal for aquariums between 2 to 10 gallons with hoods or glass canopies
  • plus-circle
    Fully submersible tank heater and can be installed vertically or horizontally

This temperature is suitable for most tropical fish. The heater does come in a few different wattages. The 50 watt version is perfect for 2 to 10 gallon tanks, whereas the 200 watt version is perfect for 40 to 55 gallon tanks.

This heater includes an indicator light that will let you know the heater is working just by glancing at it. When the indicator light is red, it lets you know that it is on and it is heating up the water.

Once the light turns green, you then know the water has reached 78 degrees. Because the operation of this heater is so simple, the heater is a great option for anyone who wants a fuss-free submersible heater.

Tetra Submersible Aquarium Heater



When looking at what people had to say about the Tetra Submersible Aquarium Heater, they had great things to say. Customers appreciated how easy it was to start using the heaters. They liked that all you needed to do was take the product out of the package, use the suction cups to stick it to the wall of the aquarium and plug it in.

They remarked the indicator lights were a great feature because they knew exactly when the heater reached temp – which was after about an hour of the unit being plugged in. One person proved how versatile this heater can be, as they use it in the water feeder for their chickens to prevent the water from freezing.

There were a quite a few people who were very upset with their purchase. The most alarming complaint some people had was that their heater reached temperatures much higher than the 78 degrees the electronic thermostat is supposed to be set at.

One customer reported the heater got so hot, it “boiled the fish alive” only after having the heater in the tank for one hour. Customers did mention that while the heater felt like it was constructed well, the temperature would fluctuate, despite the heater being set at a temperature.

Best Nano Aquarium Heater

Here are our top picks for the best nano aquarium heater:

Winner: EHEIM Jager Aquarium Thermostat Heater

The EHEIM Jager Aquarium Thermostat Heater is made from shatterproof glass. The glass jacket creates more surface space to ensure the heat is evenly distributed. The heater can be used in a freshwater as well as in saltwater aquarium. Notable features of the EHEIM Jager Aquarium Thermostat Heater include:

  • Fully submersible
  • plus-circle
    Thermo safey control protects against running dry
  • Will automatically turn off when water level dips too low
  • TruTemp dial recalibrates the heater for precise temperature regulation
  • plus-circle
    Made of shock resistant and shatter proof glass for fresh or marine water
  • plus-circle
    On/Off indicator light for at-a-glance monitoring

The TruTemp dial gives you the ability to adjust the temperature between 65 to 93 degrees Fahrenheit within +/- 0.5 degrees. The heater utilizes a mechanism called Thermo-Safety Control. This technology will turn the heater off the moment it does not detect water. This means that while you are cleaning the tank, you don’t have to worry about bumping into a hot heater.

For your convenience, the heater features a mounting bracket as well as suction cups. You can adhere the cups to the glass of your aquarium for optimal placement, be it vertically or horizontally. The heater comes with a long cord so you don’t have to worry about putting the aquarium near outlets because you have some wiggle room.

Eheim Jager TruTemp Submersible Heater



When looking at what people had to say about the EHEIM Jager Aquarium Thermostat Heater, they had great things to say. Customers raved about how evenly the heater was able to heat their aquarium. They went on to say the heater itself was fairly long, which took them by surprise because they weren’t expecting its length.

However, they did say they liked that the heater could be used horizontally, to which they were able to make it work. People also appreciated this heater is sleek and has a modern look to it.

On the other hand, there were some customers who were not as pleased with their purchase as others. These customers remarked on the overall quality of the heater. A few people have said they felt the EHEIM brand isn’t as reliable as it once was. They commented their heater wouldn’t reach (or maintain) temperature.

Some said their heaters were off by a few degrees and when they would adjust it, it would hold true for a few weeks, but then it would be inaccurate once again. There were a couple people who said the wires melted away from the body of the heater, and the glass tube filled with water. This resulted in the electrocution of the fish.

Runner Up: Cobalt Aquatics Neo-Therm Aquarium Heater

The Cobalt Aquatics Neo-Therm Aquarium is designed to give you precise control over the temperature. The dial has an accuracy of +/- 0.5 degree. Notable features of the Cobalt Aquatics Neo-Therm Aquarium Heater include:

  • Modern super flat design
  • plus-circle
    Easy to set one touch" system"
  • Accurate electronic thermostat
  • LED displays both Set Temp and Tank Temp simultaneously

There is a button on top of the heater so you can set the temperature to precisely the temperature you want, be it a cool 66 degrees Fahrenheit, or a very warm 96 degrees Fahrenheit. This wide range allows you to keep even the most tropical of fish comfortable.

The heater features an integrated thermal protection mechanism that will turn the heater off automatically once it reaches the designated temperature. This mechanism ensures the heater will not overheat, thus providing you with a layer of protection for your fish.

The heater is made from shatterproof outer casing. If you have fish that are fairly aggressive and like to throw their weight around, you don’t have to worry about your fish breaking this heater.

When looking at what people had to say about the Cobalt Aquatics Neo-Therm Aquarium Heater, they had great things to say. Customers felt that this heater was the “heater for the 21st century” in that this unit was very intuitive and gave them the opportunity to control the heat exactly how they needed/wanted to.

Cobalt Aquatics Neo-Therm Aquarium Heater



People appreciated the LED indicator and they could see what the temperature was just by glancing at the dial. Several people had mentioned they found the heater to be quite accurate and the +/- 0.5 degree claim was on point. People commented they felt the heater was constructed well and they didn’t worry when their fish would bump up against it.

On the other hand, while the majority of customers who purchased this heater had wonderful things to say about it, there were a handful of individuals who had some issues. Of the concerns customers had was that they would have liked this heater had one degree increments, instead of the 2-degree increments.

While this may be a nit-picky, sometimes that one degree can make a difference. Other customers reported the heater does not work well and after three years, their heater would go to the maximum temperature and it could not be dialed down.

This, of course, is dangerous for the fish and customers were thankful they caught this problem before harm could befall the fish.

What To Look For When Choosing The Best Aquarium Heater?

Deciding what heater is going to best suit your aquarium can be challenging, but here are some of the important things you’ll want to take into consideration before making a purchase:


The size of the heater is going to depend on the size of aquarium you have. You want to choose the best aquarium heater that is capable of heating the amount of water in your tank. This is going to be indicated by watts.

The best 50 watt aquarium heater is going to be able to heat a small aquarium, less than 20 gallons. If you have anything over 20 gallons, you will want a 100 watt heater.

Type Of Heater

There are a few different types of heaters currently available:

Combined Heater/Thermostat

This heater uses long thin glass tubes that have an adjustable thermostat on the top and the heating element is in the tube. This is the most common variety.

Aqueon Pro Aquarium Heater Setting

Separate Thermostat

The separate thermostat are easier to adjust and will keep your hands dry because the heating element and the thermostat are separated, and the thermostat is usually kept outside of the water.

Undertank Heater Mat

This type of heater allows you to place your tank on the mat and the mat warms up. The temperature is controlled with a separate thermostat. This type of heater is not recommended because they aren’t reliable and the heat doesn’t transfer through the glass and substrates very well.

Heating Cable

A heating cable is not intended to replace a traditional aquarium heater. It is best used if you want to help plants grow. The thin heating cable should be snaked through the gravel and rocks on the floor of the aquarium. Keep in mind, these cables are not necessary if you are interested in growing plants.

In-Line Heater

This type of heater is relatively new and expensive. These heaters can be used if you have an external filter. You can plumb it into the tubing between the tank and the filter. The water will warm up as it goes into the filter and then cycle back out. It’s an efficient way of warming water.

External Heater/Filter

This type of heater works much like the previous, except there is no extra plumbing involved.

Adjustment Increments For Temperature

You want to be able to have a way to adjust the temperature of your heater. Most heaters will have a dial on the top of the heater. Some heaters will have 1 degree increment adjustments, while some will use increments of 2 degrees. We recommend going with a unit that uses 1 degree increments so that you can get the precise temperature your fish requires.

Safety Features

You want a heater that is fully submersible and have an automatic shut off in case the water drops. Look for products that use “shatterproof” and “shockproof” in the product description because you can rest assured knowing aggressive fish won’t be able to break the heater and possibly get hurt or die.

Aquarium Heater Shatter Proof

Our Recommendation

Choosing the best small aquarium heater can be a challenge, but we hope the information and options we’ve provided for you will help make the decision a little easier. We like the Aqueon Pro Aquarium Heater because it is made from durable shatterproof materials and features safety features like an auto-off safety feature to prevent the unit from overheating.

If you’re looking for a great little heater for a tank smaller than 5 gallons, the EHEIM Jager Aquarium Thermostat Heater provides you with accurate temperature control, a wide temperature range, and even features safety features to prevent overheating and continuous running when there isn’t any water.

Leave a Comment: