The 10 Best Aquarium Heaters, A Complete Buying Guide

An aquarium is an exciting conversation starter, regardless of where it is placed. Whether it’s for your home or your business, you can expect an aquarium to be an eye-catching piece to an otherwise dull environment.

Since the aquarium is where your aquatic friends live, you have to make sure that they’re comfortable. As much as possible, you have to mimic the living conditions in their natural habitat. And to make sure that you do so, you have to invest in a safe and efficient aquarium heater.

The best aquarium heater should be one that’s easy to operate, offers a wide temperature range, and promises safety features for the protection of your fish. While these seem like simple standards to look into, some aquarium owners still find it hard to look for their tanks’ best heater.

In this article, we’ll talk about everything you need to know about aquarium heaters, including their wattage, the perfect one for your aquarium’s size, and the safety features that you have to look into. All of these will help you make a wise decision before buying a heater for your aquarium. But at the very first, we’ve added a list of our top ten heaters to make the search process more convenient for you.

A Quick Comparison of Top Three:

Things to Consider Before Buying

Before buying an aquarium heater, there are several factors that you have to consider first. In general, you have to consider the appropriate wattage, the heater’s size for your tank, and the safety precautions used by each manufacturer. We’ll discuss all of these in detail to ensure that you’re fully informed before investing your money in one.

Watts

The watts or wattage indicated in the heater refers to the amount of power necessary to heat the aquarium water effectively.

Like most electrical appliances, aquarium heaters also rely on electricity to function correctly. Power measures in watts and the amount of wattage necessary will depend on the size of your tank.

Right Sized Heater for Your Tank

As previously stated, the amount of wattage necessary will depend on the size of your tank. This is one factor that helps you determine what “size” of heater you need for your fish tank.

In general, the rule of thumb is that you would need 2.5 to 5 watts to heat one gallon of water. Thus, if you’re using a 10-gallon tank, you would need at least 25 watts to heat it efficiently.

However, bear in mind that this is the bare minimum, or if you’re only planning to heat the water by around 9 degrees Fahrenheit. The temperature of your surroundings also plays a big part in how well the heater will perform.

For example, if you live in a place where it’s usually cold outside, you might have to heat the water at about 18 degrees higher than the room temperature. To do so, you would need a heater capable of heating the water to your desired temperature, which usually requires higher wattage.

Nevertheless, several aquarium heaters provide us with a wide heating range. Some of them can heat the water from 68 to 104 degrees Fahrenheit, and that’s already quite impressive.

Additionally, you should also consider the heater’s dimensions, especially if you plan on using the submersible ones. This type of heater must be fully submerged underwater to function properly, so you have to make sure that the heater you buy will fit perfectly inside your tank.

Thus, when you’re looking for the best aquarium heaters, take a look at wattage and dimensions vis-a-vis the size of your tank and the temperature of your environment. These factors will greatly help you in determining the perfect-sized heater for your aquarium.

Safety Features

The heater’s built-in safety features should also be your top priority. Since the heater is powered by electricity, we understand that some breeders are wary of using this for their fish tanks. Fortunately, many manufacturers are aware of this concern, so they have decided to include safety features in their aquarium heaters.

Automatic Shut-off

One of the most common safety features is the automatic shut-off function. This means that the heater automatically turns off once the water temperature reaches the set temperature. 

Because it stops heating once it reaches a safe temperature, this gives you peace of mind that the device will never overheat. And as a result, you know that your home and your fish are perfectly safe. 
Another notable safety feature that we have come across is the automatic shut-off feature for submersible heaters if the water dips too low or when the heater is removed from the water.

If the water is too low and the heater is still turned on, it will continue heating the water at the set temperature, and it may end up being too hot for your fish. Worse, it can even melt wires and cause further accidents – and no one wants that to happen.

Other aquarium heaters have an automatic shut-off feature once it detects that it is about to overheat. This usually takes place when the heater is overworked and can cause the heater to malfunction completely.

To prevent this from happening – and to prevent further destruction – the system automatically turns itself off. This is particularly helpful when you’re not always around to monitor the aquarium’s temperature.

Automatic Restart

Working hand-in-hand with the automatic shut-off feature is the automatic restart function. This is especially useful if you live in an area where it’s always cold. This feature automatically turns the heater on once the water temperature begins to drop.

The automatic restart function allows for little supervision, so you can sleep well at night knowing that your fish won’t be too cold or too hot overnight.

Materials Used

The materials that go into your heater are also something that you have to take into consideration.

Most heaters use glass cases because glass is great at evenly distributing heat. They’re also very affordable and are not prone to corrosion. However, glass is highly breakable, and you don’t want it to shatter inside your aquarium, where all your fish are.

A more expensive alternative to glass is titanium. This material is known for its durability, heat distribution, and corrosion resistance. But while heaters made with titanium casing are more expensive, they promise better protection, which means great value for the money.

Also, while we’re on the topic of materials, be wary of heaters that contain materials that may be toxic for your pets. While these may be cheap, they may not be the best for your aquatic pets’ health.

Kinds of Aquarium Heaters

And finally, you should also determine which kind of heater will work best with your aquarium. There are different types of aquarium heaters, but there are two general types that we find very effective, which are submersible heaters and in-line heaters.

Submersible Heaters

Simply put, submersible heaters are the type of aquarium heaters that go inside your aquarium to heat the water directly. They’re great at heat distribution and can help maintain the heat inside tanks – especially if you’re using large tanks.

Also, submersible heaters are easier to install and operate, so this is recommended for most beginner breeders since it doesn’t require much work.

In-line External Heaters

On the other hand, in-line external heaters are mounted onto the filters or sump pump and heat the water as it passes through. Thus, as the water enters the aquarium, it is already heated to the desired temperature.

In-line external heaters offer better safety and peace of mind, especially if you’re not comfortable with the thought of having your fish swim next to a water heater. However, it is trickier to install than submersible counterparts.

Best Aquarium Heaters: New Arrivals

10 Best Aquarium Heater From My Choice List

1. Cobalt Aquatics Flat Neo-Therm Heater with Adjustable Thermostat

The first on our list is the Cobalt Aquatics Flat Neo-Therm Heater with an adjustable thermostat. With its simple interface and futuristic design, this is one heater that will also add pizzazz to your aquarium.

• The super flat-design on this aquarium heater allows it to heat faster, so you can count on this device to heat your machine as soon as possible. It also comes with a convenient bracket that allows you to display the heater facing inward or outward – whichever way you prefer.
• Also noteworthy is its accurate one-touch system. With the simple touch of a button, you can set the temperature you want the heater to maintain. And to make temperature monitoring easy for you, this heater with an Adjustable Thermostat has an LED screen that simultaneously displays both set temperature and actual temperature.
• We also love that the Neo-Therm comes with integrated thermal protection circuitry. This protective feature serves to shut down the heater once it detects that it is about to overheat. Thus, you don’t have to worry about unwanted accidents due to overheating.
• This Cobalt Aquatics heater with an Adjustable Thermostat is made of resin and thermoplastic, making it virtually indestructible. Compared to its glass-made counterparts, you can expect durability and longevity from this one.
• Overall, the Cobalt Aquatics Neo-Therm is a reliable and durable aquarium heater that’s worth the money. This model comes with seven wattage options that can heat fish tanks sized 6 gallons to 100 gallons.

Pros

• Designed to provide faster heat than others.
• The one-touch system makes it easy to operate.
• Its integrated thermal protection circuitry makes it convenient for users.
• Its resin and thermoplastic material makes it virtually shatter-proof.

Cons

• It is quite pricey.
• Some users note that this heater emits a foul odor.

2. Hygger Saltwater Tank Titanium Tube Submersible Pinpoint Heater

Another highly efficient aquarium heater that instantly caught our attention is the Hygger Saltwater Tank Titanium Tube Submersible Pinpoint Heater. For more details, you can check our single product review post. 

• This fully-submersible heater has to be installed horizontally for optimum performance. You can even install near the water flow to ensure that the temperature remains constant throughout the aquarium. It comes with two suction cups that keep the heater in place, ensuring that it won’t roll around all over the aquarium.
• We also love that it’s designed with a separate controller. This allows you to easily set the temperature or make the necessary adjustments without removing the heater from the aquarium. This makes it both convenient and time-efficient.
• The heating element of this Hygger Saltwater Tank Titanium Tube Submersible Pinpoint Heater is made with heavy-duty and durable titanium. It contains zero glass pieces, and this assures you that it is entirely shatter-proof. Being made of titanium material, you can also expect that this heater won’t fall victim to corrosion. Thus, this is one device that’s sure to last for a long time.
• The built-in external electronic thermostat on this heater simultaneously displays the set temperature and the current aquarium temperature. This allows you to monitor and quickly make changes to your heater. For your convenience, you can choose to show the temperature either in Celsius or in Fahrenheit.
• The Hygger Saltwater Tank Titanium Tube Submersible Pinpoint Heater also has an automatic shut-off system. Once you set your desired aquarium temperature, the heater automatically turns off once the aquarium reaches that temperature. This also serves as an added safety feature that gives you peace of mind that the device won’t overheat.
• For your reference, this heater has a heating temperature range between 32 to 104 degrees Fahrenheit. It also has a control accuracy of more or less 0.5 degrees Celsius, so keep these in mind when you’re setting the temperature.
• The Hygger Saltwater Tank Titanium Tube Submersible Pinpoint Heater is mostly designed for saltwater, and it is the best saltwater aquarium heater, in our opinion. Although it is versatile, you can use it for your freshwater aquarium, turtle tank, or reef aquarium. 

Pros

• It has a convenient design with an external thermostat and a separate controller.
• It is fully-submersible, which makes it easier to heat the entire tank.
• It is made of heavy-duty and durable titanium.
• You can use it for a variety of tanks.
• It is highly adjustable.

Cons

• Some users note that they experienced temperature fluctuations with this heater.

3. Aqueon Adjustable Pro Heater

Another fully submersible aquarium heater that we love is the Aqueon Adjustable Pro Heater.

• This heater allows you to adjust temperatures between 68 to 88 degrees Fahrenheit, with an electronic thermostat accuracy of more or less 1 degree Fahrenheit. This makes it perfect for freshwater or saltwater marine life habitats.
• The Aqueon Pro Heater should be fully-submersible in water, and you can install it either horizontally or vertically on your tank. Thanks to its strong suction cups, you don’t have to worry about your heater being all over your tank.
• We also love that it has a convenient LED light display. When the indicator light is red, it means that it is heating; on the other hand, it tells you that it is not heating when it’s green. This is a convenient feature that instantly tells you when the device is working or not.
• The Aqueon Pro Heater also has a protective feature when it overheats. The part automatically shuts off in case of overheating and immediately restarts once it starts to cool off. This means that you don’t have to keep your eyes glued to your aquarium to monitor your heater.
• This heater’s heating element is made of strong material that’s non-corrosive and even boasts of being nearly indestructible. This guarantees both durability and longevity, thereby giving you great value for the money. It also allows for a more even heat distribution, so the tank heats up as fast as possible.

Pros

• It is very affordable.
• It can be installed in two ways.
• It has a convenient indicator light when the heater is working.
• It has a strong and durable shell.
• Its automatic shut-off and restart functions make it very convenient.

Cons

• It has a limited heating range.
• Some users note that the thermostat is not very accurate.

4. Fluval M Submersible Heater

We highly recommend the Fluval M Submersible Heater for those looking for an affordable yet durable heater.

• This heater has a temperature heating range between 66 and 86 degrees Fahrenheit. This makes it ideal for setting temperatures for freshwater and saltwater aquariums.
• We also love that the Fluval M Submersible Heater comes with built-in reflective technology mirrors. This feature allows it to blend naturally into your aquarium’s environment, so you wouldn’t have to deal with a heater that’s an eyesore.
• Additionally, this aquarium heater is made from a combination of Borosilicate glass known for its shock-resistant properties and a high-density ceramic heating element that’s known for quickly heating up. This makes it both cost-effective and reliable.
• The slim Fluval M Submersible Heater makes it easy to install, while its suction cups allow it to latch onto your aquarium securely. We also love that it’s easy to install, so even beginners can set it up without any problem.
• Overall, the Fluval M Submersible Heater is an affordable and reliable aquarium heater that’s also very easy to install. And thanks to its superior components and construction, you know that this is something that will last you for quite some time.

Pros

• It is very affordable.
• It is effortless to install and operate.
• Its slim design is convenient and makes it easy to install on a variety of tank sizes.
• Its mirror technology allows it to blend in.

Cons

• It is made of glass, so it is not shatterproof.
• Its heating range is limited.

5. ViaAqua 300 Watt Titanium Heater

The ViaAqua 300 Watt Titanium Heater is another top contender for one of the best aquarium heaters in 2021.

• Boasting a titanium heating tube, you can expect the utmost durability from this heater. Titanium is also known for being corrosion-resistant, so you know that this is something that you don’t have to replace often.
• This aquarium heater has equipped with one of the best aquarium heater controllers with a large LCD screen that’s easy to read. It allows you to easily set and adjust the heater’s temperature without taking out the device from the aquarium. It also displays the temperature in Celsius or Fahrenheit, whichever is most convenient for you.
• Aside from the controller, the ViaAqua 300 Watt Titanium Heater also has a remote temperature sensor. These sensors are known for their accuracy since they are situated away from the heater – which means that its reading is not affected by the heat emitted by the heater.
• As a safety precaution, the ViaAqua 300 Watt Titanium Heater comes with an automatic shut-off function in case it overheats. This gives you peace of mind, knowing that the heater won’t cause an accident.

Pros

• It is made of durable titanium.
• It comes with a high-accuracy remote sensor.
• The LCD screen is very convenient when you have to make adjustments to the temperature.
• It is easy to install and operate.

Cons

• It only works on 120-volt power outlets.
• It is 10.5 inches long, so it won’t fit in smaller tanks.

6. DaToo Aquarium External Heater

If you’re not comfortable with the idea of having a fully submersible heater with your marine friends, then you might want to consider the DaToo Aquarium External Heater.

• This aquarium heater is ideal for using a canister filter to provide their aquatic pets with a comfortable environment. This will provide them with an over-heat system that’s perfectly safe for them.
• The DaToo Aquarium External Heater also boasts a leading temperature control system that’s precise and capable of maintaining the water’s temperature. This is all thanks to the advanced STM8 chip used by this heater.
• This aquarium heater also has a clear and large LED screen that helps you monitor the temperature inside your aquarium. This also helps make adjustments easier. Additionally, this heater has a heating range between 68 and 95 degrees Fahrenheit, a more extensive coverage than its competitors.
• The DaToo Aquarium External Heater comes with two temperature sensors located at the inlet and outlet. It allows it to measure the temperature accurately, so you’re assured that what’s displayed on the LED screen is the actual temperature inside the aquarium.
• We also love that this aquarium heater has an automatic shut-off feature. Once the aquarium temperature exceeds the set temperature by 0.2 degrees Fahrenheit, the heater automatically turns off to ensure that the temperature is comfortable and safe for your fish.
• Additionally, the DaToo Aquarium External Heater has an imported glass-ceramic heating tube that’s shatterproof and explosion-proof. It is made of premium material, so you know that it’s very durable. On the other hand, the shell is made of sturdy ABS plastic, making it virtually indestructible.
• Without a doubt, the DaToo Aquarium External Heater is the best external aquarium heater for those on the lookout for a safe and reliable over-heat system without breaking the bank.

Pros

• It has an impressive temperature range.
• It is built with an automatic shut-off feature.
• It is made of durable and shatterproof material.
• It comes with two temperature sensors to guarantee accurate readings.
• The unique temperature control system coupled with the LED screen makes adjustments easy

Cons

• As of the time of writing, there are no negative reviews of this product

7. ISTA In-Line External Heater

Another external heater that you might want to consider is the ISTA in-Line External Heater.

• This aquarium heater is made with thermally-sprayed glass that makes it heat faster than other heaters. This allows it to save more energy while still being able to heat the whole tank effectively.
• The ISTA in-Line External Heater comes with two temperature sensors. The first one is located at the inlet, while the other is located at the outlet. These two sensors allow it to get more accurate measurements of the tank’s temperature to help you make the adjustments accordingly.
• Because it is designed to be used externally, this aquarium heater doesn’t take up space inside your tank, thereby leaving you with more space for your aquatic friends.
• The ISTA in-Line External Heater is one of the heaters that are easy to install and operate, so you don’t have to ask a professional to do the installation for you. And that saves you a lot of money from having to hire one.

Pros

• It heats up faster than others.
• It comes with two temperature sensors.
• It is easy to install and operate.

Cons

• Some users note that the screen inside the heater tends to clog and blocks the flow of the water.
• It is not very durable.

8. Hydor In-Line External Heater

The Hydor In-Line External Heater is the perfect aquarium heater that wants an eye-catching heating device for their tanks.

• Thanks to its sleek design, this in-line external heater won’t be an eyesore for your aquarium. But aside from its impressive aesthetics, this heater also boasts a high-precision electronic temperature control to make sure that you will be able to set the most comfortable environment for your fish.
• The Hydor In-Line External Heater also has a self-limiting Positive Thermal Coefficient. This is an exclusive technology from Hydor that prevents the device from overheating. Thus, you can expect high-quality performance from this heater while also being assured of its built-in safety precautions.
• This heater is perfect for canister filters and sump pumps, whichever you prefer for your tank because of its inline external design. We also love that the Hydor In-Line External Heater is very easy to use, so installation and temperature adjustments will be a breeze.
• Overall, the Hydor In-Line External Heater is a great external aquarium heater for marine and tropical aquariums. Additionally, the self-limiting PTC function puts all other heaters to shame.

Pros

• It is made of premium and durable materials.
• It is easy to use and operate.
• Its self-limiting Positive Thermal Coefficient gives you peace of mind as to your safety, as well as the safety and comfort of your fish.
• It comes with a sleek design that’s easy on the eyes.

Cons

• Considering what it offers, it is quite pricey.
• Some users note that this heater tends to leak.

9. Eheim Jager Aquarium Thermostat Heater

We have chosen Eheim Jager Aquarium Thermostat Heater as one of the best aquarium heaters of 2021 for so many reasons.

• One of the things we love about the Eheim Jager Aquarium Thermostat Heater is that it gives users eight wattage options to choose from. This assures them that there’s a corresponding Eheim heater for fish tanks of different sizes.
• Aside from the wide variety of wattage options, this aquarium heater also has an impressive temperature range between 65 and 93 degrees Fahrenheit, making it perfect for various tanks. You can easily switch to the temperature you want using a TruTemp dial, convenient and easy to calibrate.
• The Eheim Jager Aquarium Thermostat Heater thermo-safety control feature that protects in case the heater is running dry. This means that the heater shuts off immediately when removed from the water and turns itself back on once it is fully-submerged again.
• We also love that it has an indicator light that tells us when it’s heating or not. This makes it easier for us to determine if it is efficiently heating the tank without removing it from where it is mounted.
• The Eheim Jager Aquarium Thermostat Heater is made of shatterproof glass resistant to pollutants, chemical substances, and biological substances to reduce the need for cleaning. It can also withstand extreme temperature fluctuations, so you know it’s something that can last for a long time.
• This aquarium heater also comes with a glass jacket that effectively enlarges the heating surface – this means that it can heat the water fast and evenly. It also comes with a mounting bracket with suction cups that help secure it in place and wherever you want to place it inside your aquarium.

Pros

• It produces an impressive heat output.
• It is made from shock-resistant and shatterproof glass.
• It is perfect for fresh or marine water.
• It comes with a convenient Thermo-Safety Control feature that automatically turns off when it is no longer fully-submerged in water.
• It has impressive temperature regulation and recalibration control.

Cons

• Some users note that this device tends to overheat and melt its wires.

10. Orlushy Submersible Aquarium Heater

Completing our list for the top ten heaters for aquariums is the affordable and reliable Orlushy Submersible Aquarium Heater.

• Despite its affordable price tag, this heater can precisely heat your aquarium with temperatures ranging from 68 to 89 degrees Fahrenheit. It has a margin of error of more or less one degree Fahrenheit only, so you get a decent estimate of what the water is inside the aquarium.
• The Orlushy Submersible Aquarium Heater has a fully submersible design that efficiently heats the water inside the tank. It is made of a 2-millimeter thickened quartz glass that’s durable and explosion-proof. This helps it blend easily inside the aquarium, while its strong suction cups allow it to stay securely in place.
• Also noteworthy is that this heater can be easily adjusted in small intervals so that you can make the necessary temperature changes with ease. Its external digital thermometer displays the temperature either in Fahrenheit or Celsius, so you can choose which one is most convenient for you.
• The Orlushy Submersible Aquarium Heater also has an automatic shut-off feature that turns the heater off once it reaches the desired aquarium temperature. This assures you that overheating won’t occur, thereby preventing any untoward hazard to your fish and home.
• Overall, the Orlushy Submersible Aquarium Heater is an affordable alternative who are looking for a reliable submersible heater for their aquarium. It is available in four sizes, which can heat aquariums with sizes ranging from 15 gallons to 80 gallons.

Pros

• It is very affordable.
• It is easy to install and highly adjustable.
• It comes with an external thermometer that displays the temperature in Celsius and Fahrenheit.
• Its strong suction cups securely hold it in place.
• Its automatic shut-off function is a great safety feature.

Cons

• Some users note that temperature adjustments are not always accurate.
• It is made of glass, which may still be susceptible to breakage.

Video on How to Choose an Aquarium Heater

FAQs

Here are the answers to the frequently asked questions that we often receive to give you a better understanding of how aquarium heaters work.

Where should I put my heater in my fish tank?

The answer to this question would depend on your preference. But while most people prefer a heater that adds to the aquarium’s overall aesthetics, we recommend installing your heater near the circulation pump. This allows it to heat the water as it enters the aquarium so that the temperature remains constant.

Most submersible aquarium heaters come with suction cups that securely hold them in place. You can put it vertically or horizontally – this would depend on your preference and how much space your tank can offer.

Should aquarium heaters be fully submerged?

There are several kinds of aquarium heaters, and only the submersible ones should be fully submerged. These submersible heaters work to regulate the temperature from inside the tank and under the water, so they must be fully submerged to function effectively.

How long should I keep my aquarium heater on?

There are so many factors contributing to how long you should keep the aquarium heater on. First is the fish’s ideal temperature in your aquarium, and the second is the temperature outside.

If you’re breeding fish that aren’t comfortable in water that’s too hot, then you shouldn’t keep your heater turned on for too long. Additionally, if it’s freezing outside, it would take longer for the water to heat up. Thus, the time you have to keep your heater on would depend on these factors.

Should I turn my fish tank heater off at night?

For safety measures, it is advised to keep the heater off at night. However, this may not be advisable during the cold winter months when the surrounding temperature can instantly drop below 0 degrees.

We advise getting a heater with an automatic feature that turns off when it already reaches the ideal temperature and then restarts once it gets too cold. This is both cost-effective and saves you the hassle of having to monitor the temperature in your tank in the middle of the night.

Are aquarium heaters dangerous in terms of electrocution of fish tank water?

In general, aquarium heaters are perfectly safe for your fish. They are made of materials that do not conduct electricity, so you shouldn’t worry about accidentally getting your fish electrocuted. But as a safety precaution, always make sure that the heater you’re getting has passed the industry’s safety standards to prevent any form of accident.

How often should I replace an aquarium heater?

Ideally, a premium aquarium heater will not require frequent replacement. But as a safety precaution, you have to take it out once in a while to see if it still functions efficiently; otherwise, it already needs replacement.

Experts advise checking in on your heater once or twice a year for this purpose. However, most fish tank heaters require replacement once every three to five years.

Final Words

The best aquarium heater should give your fish the ideal environment that they will live in. Since their bodies are incapable of regulating temperature, you must help them stay comfortable with the help of a fish tank heater.

Before buying one, you should first check out the aquarium’s size and what type of heater would work best for that size. This will assure you that you’re creating the best environment for your beloved aquatic friends.

Also, make sure that these heaters come with added safety features. Not only will these features prevent it from making it too hot for your fish, but they will also give you peace of mind that your home is never in danger from heater-related accidents.

With all these in mind, we’re sure that you’ll be able to find the best heater for your aquarium. And if you’re still uncertain of your choices, then don’t hesitate to take another peek at our top ten tested-and-proven picks.