Best Aquarium Heaters 2021 – Reviews & Buyer’s Guide

Last updated on December 24th, 2022 at 11:05 am

Best Aquarium Heaters 2021

Choosing the best aquarium heater for your aquarium is important if you want your fish to thrive.

It’s that easy.

Fish depend solely on the heat of the water to maintain their own body temperature. This means that if your aquarium heater is not doing its job, it can be dangerous to the animals that live there.   

However, it can be difficult to determine which aquarium heaters are the best and which ones are right for your tank setup.

That is why we have worked hard for you.

Each of the aquarium heaters on our list has gone through a careful research and evaluation process and is otherwise undamaged.

Let’s start without further ado:

Best Aquarium Heaters 2021 – Reviews      

Because aquarium heaters are such an important piece of equipment, we had to do a lot of research to make sure we were happy with our choices.

When we finished, we had narrowed our initial list of more than 40 heaters to six.

That is how:

We use bad reviews, weird specs, and irrelevant companies to truncate the list, to begin with quickly.        

We then went to the weeds and looked at the heaters’ details left on our list (price, specs, etc.).

More recently, we have received feedback from the farm and have had our hands on these heaters whenever possible.

This process gave us our list of the best aquarium heaters that you can see below. So far, we have received excellent feedback, and we know you will find it useful.   

1. Neo Therm Cobalt Aquatics Flat Heater   

Best Aquarium Heaters 2021

Modern, fully submersible design for energy-efficient aquarium heating

Set the temperature by simply pressing a 66-96 ° F button, and the neothermische electronic thermostat maintains the correct temperature              

Built-in thermal protection circuit prevents the heater from overheating

Unlike low – cost devices, heating glass is the Neothermie, a heater resin / thermoplastic outer housing with shockproof                 

The prelude is the Geotherm heater from Cobalt Aquatics. Cobalt is known to make great products, and that certainly applies to this heater.         

This is an immersion heater that looks amazing and works great. It has a temperature range of 66 ° F to 96 ° F, giving you many options for the type of fish it is compatible with. Depending on the selected model, the power range is between 25 W and 300 W.      

The design is slim and flat. This means that it does not take up much space in your tank or take your eyes off the rest of the tank. However, when you look at the radiator, it won’t be a thorn in your side. This is perfect for the aquarist who takes the aesthetics of their aquarium very seriously.          

One of the things we love about this aquarium heater is the safety and reliability you get when you buy it. Cobalt has a 3-year warranty, and they won’t fight you if you have a problem (which you probably won’t).   

This submersible aquarium heater comes with a shatterproof outer shell that almost guarantees that this will remain intact. It also comes with some pretty advanced internal protections that prevent overheating and a reliable auto-shutoff feature.           

It also has a clear LED display that makes it easy to see your tank temperature and what temperature your heater is set to.


· Very reliable

· It comes with a 3-year warranty.

· Unbreakable outer shell

· Looks great

· LED display is easy to read

· Lots of great reviews online


· Expensive

· Problems have been reported with the suction cups provided

2. The Fluval E electronic radiator. 

Best Aquarium Heaters 2021


This heater is a prevalent option in fish farming for several reasons.

It has a sleek design that looks great in almost any tank and is a very affordable purchase. It is also quite compact, which means it can easily be put out of reach as a submersible aquarium heater.   

There are three power options for this heater: 100W, 200W, and 300W. Easy to remember!   

The Fluval E electronic radiator heats water surprisingly quickly. This was something we did not expect, given the compactness of the device. It has a range of 68 ° F to 93 ° F.                 

It also comes with a well-designed LCD screen that shows you the temperature and clarifies if the water temperature is not where it should be.

Fluval also offers a 5-year warranty on this product, which we think is great. It is very reasonably priced compared to other aquarium heaters. 5 years is a long time!                    

There is also effective fish protection that prevents fish or invertebrates from coming into contact with this immersion heater.

Installation is easy too. It comes with a side glass adapter if you can’t mount it to the rear wall of your tank. In general, you should be able to get this heater up and running in 30 minutes if you follow the instructions.                  


· Acceptable price

· 5-year warranty

· Heats the water quickly

· Well created

· Easy-to-use LCD and temperature control


· You need a good amount of water

· Some issues have been reported with fluctuating temperatures

3. Hygger Compact Aquarium Submersible Heater   


Best Aquarium Heaters 2021


This is the first of the two more hygge aquarium radiators on our list.          

Simply put, this is just a sturdy little heater. There really isn’t one sure thing that surprises you, and it just does its job.   

It may not be as noticeable as some of the other heaters on our list, but don’t be fooled by that. This is an aquarium heater that packs a punch (assuming you’re using it with the correct tank size).   

You use a dial on the power cord to adjust the temperature, and you should expect the water temperature never to vary more than 2 ° F. It has a temperature range of 75 ° F to 91 ° F, which should be enough to make the I work on most tanks.   

The Hygger has an automatic shutoff if problems of heating or the water temperature exceed 2 ° F for above the setpoint. In this case, the system automatically returns as soon as the temperature drops below 2 ° F from the set point.                       

This is an immersion heater delivered with delicious quality suction cups that allow you to attach it to the tank’s side easily.        

You can choose three watts with the Hygger: 50 W, 100 W, and 300 W.                


· Affordable option for most tank owners

· Reliable temperature protection

· Strong suction cups that ensure they stay attached to the side of your tank

· According to Hygger, you can expect this aquarium heater to work for at least 3 years           


· It feels a bit dated compared to some of the other heaters on our list.

· It can only be used in glass tanks.

4. Eheim Jager Aquarium Thermostat Heater       

Best Aquarium Heaters 2021


8-watt options for a variety of tank sizes

Fully submersible

The switching temperature safety protection against dry running      

Made of shatterproof and shatterproof glass for fresh or seawater

This is another solid aquarium heater that is very well rounded and will not disappoint. It’s also very attractively priced, which may make it a good buy for many new owners who don’t want to make extra money for something like the Cobalt Neo-Therm.                 

The Eheim is fully submersible and has the standard safety features you would expect from the best aquarium heaters. This means that when the water temperature exceeds the safe fluctuation range, it turns on or off.         

There are many wattages you can get with this heater. Here you are:   

· 25 W

· 50 W

· 75 W

· 125 W

· 150 W

· 200 W

· 250 W

· 300 W 

It also has a nifty feature that ensures it doesn’t dry out. When the water level drops below an acceptable point, it will deactivate to avoid problems that could affect your tank or life.               

You’ll also find a shatterproof, shatterproof glass design to keep you safe. It’s honestly at this point something we’ve come to expect from just about every best aquarium heater out there, but it’s nice to see it available at such an affordable price.    

There’s nothing on this heater that can hit it, but that doesn’t mean it’s a bad thing. It’s affordable and gets the job done, and there’s nothing more to say.   


· Auto shutoff function when the water level is low

· Comes with a standard 3-year warranty that is very competitive

· The temperature fluctuation is very reasonable.


· It takes up a lot of space in your tank

5. Hygger Digital Titanium Submersible Aquarium 


Best Aquarium Heaters 2021

This heater – submersible aquarium water Hygger stands out from most other models on our list.           

While most other heaters are plastic and have a dark design, the Hygger stands out. It has a titanium heating element that can work in both fresh and saltwater. This design makes it very resistant to all the standard seawater problems that plague many other heaters.            

It also means that it is very durable. Titan is not a joke!   

The Titan- Hygger has four watts to choose from :         

· 50 W

· 100 W

· 200 W

· 500 watts

Another feature that sets this heater apart from the crowd is its huge temperature range. Most of the best aquarium heaters can range from 20 ° F to 30 ° F for possible water temperature options, but the hygger will get it out of the water.                     

We are talking about a range of 32 ° F to 104 ° F.

It is easily the best of the series and covers almost all types of aquatic life you place in your aquarium. It also comes with a very efficient temperature monitoring and control system.   

With this heater, you can expect minimal fluctuations in water temperature. It will almost always be within 1 ° F of what you set.   

For this reason, it is one of the best aquarium heaters, and it is straightforward to make this list.        


· Absurd temperature range (in a good way)

· Very little fluctuation in water temperature

· Built to last

· Unique model


· It can only be used for glass tanks.

· Limited mounting / housing options

6. FREESEA heater with LED temperature indicator

Best Aquarium Heaters 2021

Lastly, we have a small FREESEA aquarium heater. It is a complete option that can be used in tanks from 1 to 50 gallons and at a very reasonable price.   

This immersion heater has a very attractive and compact design that can be stored practically anywhere in your tank. We think it’s one of the prettiest heaters on the list.   

Even though this device is small, it has a very impressive temperature range (second best on our list) of 59 ° F to 94 ° F. We honestly don’t know how they did it!   

It has an excellent LED display that allows you to monitor the water temperature in your tank without distraction easily.

The various devices have a power range of 50W to 300W and have all the standard safety features you would expect from a quality manufacturer.            

The biggest drawback we can find with this heater is that it only comes with a 12-month warranty. However, we can’t blame FREESEA here because it is very affordable and has a wide range of features.    


· Excellent value

· Attractive design

· Well-made LED display with temperature adjustment

· Impressive temperature range


· The radiator must be constantly submerged to achieve results.

· The 12-month warranty is the lowest on our list.

Why Your Fish Need High-End Heating

Best Aquarium Heaters 2021

As we have said before, the importance of finding a good aquarium heater cannot be underestimated.

These are some of the main reasons why:

Your aquarium’s overall goal should be to mimic the ecosystem your fish live in concerning the water conditions. Everything must be stable and safe.   

If your aquarium heater poorly regulates the water temperature, it can lead to serious health problems for your fish (sometimes even death).

For this reason, in our opinion, it should never be considered a “good enough” warm-up. Even if they operate 95% of the time, fluctuations in water temperature can be enough to destroy the life of your tank.    

You must demand perfection and reliability from the aquarium heater you choose.

What to look for in the best aquarium heater

After reviewing our list of the best aquarium heaters, let’s take a moment to consider the characteristics to consider when making your decision.

Level of security      

We put this first because we believe it is non-negotiable. All of the best aquarium heaters have a very high level of safety and reliable safety features.   

You see, some tank owners risk a cheap heater that works most of the time. 

We do not compromise in any way the safety and health of the aquatic life in our pools. This is how we drive.   

The price difference between a cheap aquarium heater that works most of the time and a good quality water heater that works all the time is quite small. The best heaters will last a few years. So why take the risk of more than twenty dollars?     

The most important safety features to look for are the ability to shut off when the temperature is too high automatically, or the water level is too low. It is not worth buying an aquarium heater that cannot offer this.   

You also want a simple, reliable way to monitor your water temperature and an indicator light to know if your heater is on or off. Today this usually comes in the form of an LED or LCD screen, which makes it easy for you.   

Performance in relation to the size of the aquarium      

You’ve probably noticed that on our list of the best aquarium heaters, we’ve included a performance in every product review. If you’ve never bought a radiator before, you might be wondering why.   

The wattage of your heater indicates how much energy it has. Simply put, it indicates how much the water in your tank can be heated.   

You don’t want an aquarium heater that is too weak for your aquarium, nor do you want a heater that is too powerful.

The general formula is 3 to 5 watts per gallon of water in your tank.

Water temperature control

You rarely see heaters on the market these days without the ability to choose a specific temperature, but it’s worth mentioning in case someone is trying to help you out.

The ability to adjust the temperature at will is a must for all tank owners. Different aquatic creatures need different water temperatures to thrive, and you must be able to provide that.   

The price

It’s a bit of a no-brainer, but we’ve included it because we think it’s important to consider price expectations with the best aquarium heaters.

As you probably guessed from our mini-rant, we are never fans of the cheapest option when it means sacrificing the safety or well-being of life in your tank.

However, we manage to keep money from growing on trees. 

This is why we are so happy with our list. It contains high-quality radiators at varying prices, giving you the freedom to choose the best for your tank and wallet.   

If price matters, you should be able to take into account that you are choosing two heaters. We’ll cover this in more detail in the next section, but of course, if you choose to go this route, you’ll need to budget.

Types of Heaters of the Aquarium

Before we dive into the aquarium heater review guide, we thought it would be prudent to list the different types of heaters available in the market.

If you have a little more experience and already know what type of heater you need, you can skip this section. Otherwise, we recommend that you take a look.   

Submersible Aquarium Heaters

We wanted to start with submersible aquarium heaters, as this is one of the most common types. Some of the heaters on our test list below are also submersible. Therefore, everyone must understand what it is about.     

In short, a submersible aquarium heater works by placing it in the tank and below the surface of the water. There you can heat water very efficiently.   

In fact, it is one of our favorite species.

The reason is that submersible aquarium heaters are masters of consistency. Being directly in the water (compared to other heaters), you can easily control and influence the water temperature.   

They are also very easy to configure. This combination of high performance and easy-to-use setup is why they’re so popular right now (and probably will be for a long time).   

Immersion heaters

Hanging heaters are another name for submersible aquarium heaters, and you will find that the two sets are used interchangeably.

As you may have guessed, an immersion heater is mounted and suspended above the water in your tank. Apply heat from top to bottom to warm the water.   

Immersion heaters have certain advantages and disadvantages.


· They are affordable

· Often included in delivery


· This can make it difficult to move the tank lid/hood when you need to open it.

· It does not provide the same efficient and uniform heating as immersion heaters.

Certainly, there are submersible aquarium heaters that do this job, and we don’t beat them all. It should only be noted that you are likely to switch to a different type of heating at some point.   

This type of aquarium heater works a little differently than the first two on our list. Instead of heating the water that is directly in the tank, an in-line heater works like magic along the chain.   

What does it mean?

Simply put, an in-line heater is placed in the sump or in front of the filter. As the water circulates in this area, it is heated by the in-line heater.   

The advantage of this is that you can keep your tank neat, clean, and without additional equipment.

This is perfect for aesthetics but also for functionality. Some fish and aquatic life can be aggravated by foreign objects in your aquarium.   

By keeping your aquarium heater out of sight, it will keep you happy and stress-free.

The main disadvantage of in-line heaters is their cost. We generally don’t recommend them unless you think some other type of heating will bother your fish.   

Substrate heaters

You won’t see many of them anymore, but they are worth adding to the list as they were so popular. For this reason, there are still quite a few floating around.   

Aquarium substrate heaters heat water from the bottom up. The cables are mounted to the bottom of your tank, where they emit heat to the water.   

As you may have guessed from all the “cables to connect to your tank,” these can be a bit expensive.

If you compare that to the ease of simply throwing an immersion heater into the water, it’s pretty obvious why the aquarium community has turned away from it.


What Makes A Great Heater For Your Aquarium?      

Let’s take a look at some key features to consider when finding the right heater for your aquarium.

Available watts

Power is the power of the radiator. Determine the ability to heat and maintain the desired temperature in your aquarium.   

Typically, you need 3 to 5 watts per gallon of water. I would also recommend using two heaters instead of one super-powerful heater.                 

Make sure you don’t buy a heater with too much power for your tank. A 100-watt heater would be too much for a 10-gallon tank :         

· 50 watts – suitable for aquariums up to 15 gallons

· 100 watts – suitable for aquariums up to 30 gallons

· 200 watts – suitable for aquariums up to 65 gallons

· 300 watts – suitable for aquariums up to 100 gallons

Adjustable temperature

You want to be able to adjust the temperature setting of your radiator.

It sounds silly, I know, but some heaters have a fixed temperature. If for some reason you need to change the temperature, it will be impossible.   

The best aquarium heaters always have adjustable thermometers.

Access to commands      

Again, this seems like a no-brainer, but if you don’t make sure you can easily adjust your underwater heating, it can be a very frustrating process.

You want to look for heaters with a large control knob that is easy to grip and turn when submerging.

Temperature readability

In my opinion, the best aquarium heaters come with digital temperature gauges. You need to make sure that you can easily see this number.              

Please note that this number may not always be accurate. It is also recommended to have a thermometer.                   

Safety devices

First of all, make sure that the heater you bought is completely submerged. Most are, but you better be sure.  

The automatic shutdown functions are very good.

These automatically turn off the heating if the water level is too low or if the temperature in your tank is too high.

An indicator light is the next safety feature that I like to see. This means that the heater has a light when it is on and when it is actually heating.   

You want to know if your heater is really on, or you need to monitor it constantly.

Best Aquarium Heaters 2021 – FAQs

If you’ve never bought an aquarium heater before, you’re probably asking yourself some questions. While we may not be able to read your mind (which would be great), there are questions that we’ve heard a lot over the years.   

We’ve answered those questions below, and we’ll add the ones we frequently hear to the list over time. If you have any other questions, please contact us directly.   

How many heaters do I need?

This is a question that we receive a lot because of the variety of information that is circulating.

If you look at all the aquarium heater product pages, it says that any one of them can heat your tank on its own. However, if you speak to experienced aquarists, you will hear that some heaters are a good idea.   

Then what is   

Here is our position:

One of the best aquarium heaters can heat the water in your aquarium on its own. This is not a fake advertisement from the manufacturer.   

But if you can handle it, getting two is usually a good decision. This makes it very easy to keep your water warm regardless of the conditions you live in.               

Not all heaters have to work as hard, and if one of them fails, you have another one that works completely as a backup.

If you decide to do this, make sure you have two heaters well below the recommended total for your tank size.

How to configure it?

Running your aquarium heater is much easier than you might think. Heaters these days are ready to go. There are only a few things you want to do first.     

Note: It is important that you do all of this without fish in the aquarium. This may seem obvious to some of you, but just mention it to be sure.    

Clean the glass where you want to mount it. The glass inside your tank could probably be cleaned quickly to make sure the suction cups stick easily. You need to make sure the radiator is near the filter inlet or where there is a flow of hot water.       

Follow the instructions to mount the radiator. Today, modern aquarium heaters (submersible boats at least) are assembled in much the same way. When following these instructions, follow the instructions to make sure they are assembled correctly and safely.             

Give it a moment. You will likely need to install your aquarium heater before turning it on. Each manufacturer has its own recommended time. So respect the time indicated in the manual.         

Perform a temperature test. Use a thermometer to check the water temperature before turning it on. This will give you a baseline that you can use to make sure your new heater is working.       

Turn it on and wait. Set your heater to the desired temperature for your tank water and wait about a day before checking again. Once you have confirmed that your aquarium heater is working properly, it is time to add your fish to the aquarium.       

How do I make sure it works correctly?

The short answer is that you need to use an external thermometer (not connected to your heater) to verify that your heater is working and give you an accurate reading.

It’s something you have to do consistently just to be safe. It does not take long and will be of great help to protect your aquatic life. A quick daily check doesn’t take long and gives you peace of mind (especially if your heater is always on the new side).      

1 thought on “Best Aquarium Heaters 2021 – Reviews & Buyer’s Guide”

  1. Excellent website. Plenty of helpful information here. I am sending it to a few pals ans also sharing in delicious.
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