10 Best Aquarium Heaters 2021: Help You Review and Buy a Good Aquarium Heater

Owning an aquarium is great and a dedicated hobby, although it can be extremely challenging, more so than having a cat or dog. There are a lot of criteria to be fulfilled for the fish in the aquarium to feel fed, comfortable, and cozy enough.

One of those criteria is owning a good and reliable aquarium heater that will elevate the temperatures to the most suitable level. If you’ve just built a water tank and are approaching the stage of buying an aquarium, here are the best aquarium heaters we found, as well as a buyer’s guide that will help you get started on maintenance and different types of aquarium heaters.

Different types of aquarium heaters

Ever since owning a fish aquarium has grown in popularity and become physically possible without having the fish and the entire ecosystem suffer, the tanks have been receiving a lot of improvements as well as heaters. That’s why today, we have a lot of heater types that cater to different aquarium ecosystems. If you want to own an aquarium but don’t know which heater is the right for you, here is a list of heater types that you may come across when shopping.

  • Immersible Heater usually hangs in the aquarium, located on the rear of your aquarium. Its heating element is enclosed inside the glass tube, and then it’s put into the water. This is one of the most common types of aquarium heaters, and it’s more affordable compared to the other options.
  • Submersible Heater is designed to be put directly into the aquarium, and as such, there are more spots in the tank where it can be put. Any place is suitable as long as it’s not touching the substrate or the decoration for the fish that could actually cause a fire to emerge. Additionally, you need to make sure that despite placing that heater, fish will still have space to swim effortlessly.
  • In-Line Heater works exactly close to the filtration system by being hooked to it. Consumers usually place it between the tank and the filter. If you have a larger tank and are looking for a power-efficient option, this is the best option for you.
  • In-Sump Heater can be found in your sump system, as its name suggests. These heaters are designed to be more space-saving so that fish would have more space, and that they offer about the same benefits as the in-line heaters, although they consume more space.

Research for choosing the best aquarium heater

As mentioned above, looking after a fish aquarium can be more demanding than looking after a dog or a cat. That said, when you’re springing for the best aquarium heater, you must consider the fish you want to host in there.

Now, most aquarium hobbyists look after tropical fish species to look after, because they come in more vivid colors. With so many species available in the market you need to learn each individual fish’s requirement and how to look after them, as well as the amount of heat they need to survive.

Although water quality is of the utmost importance when looking after fish, you also need to learn how to maintain the proper temperature to make your new pets feel sufficiently warm and comfy. Changing conditions in aquariums can stress fish in great matters, which is why it’s important to consider the right temperature when adjusting it for the number of fish you’ll get.

10 best aquarium heaters 2020


Now that we’ve touched all the types of the aquarium and how to maintain one, it’s time to review some of the best aquarium heaters we’ve picked. We’ve also listed all the advantages and disadvantages of using them, as well as the types. It’s up to you to pick the right aquarium heater based on the features we listed below, as well as other criteria like the size of your tank, location, and more. Good luck!

1. Fluval E Electronic Heater – best premium aquarium heater

  • Price: $$
  • Type: Submersible heater
  • Wattage: 100, 200 and 300-watts
  • Warranty: 5 years

We focused this review on comfort, reliability, and quality, and Fluval E Electronic Heater delivered much more than that. Its robust and compact design makes it able to adjust to any type of aquarium, providing accurate and real-time temperature thanks to its dual temperature sensors that it comes with. Being available in multiple wattages, it is adjustable to any type and size of a tank that is used. Additionally, you can choose to measure temperature in the tank using both Celsius and Fahrenheit measurements. Also, you can increase the temperature with the 0.5-degree increment between 68 and 93 degrees Fahrenheit.

In addition to great design, it’s extremely customizable and can’t be mounted at any angle thanks to its mounting bracket, which makes viewing the display extremely easy. It is equipped with a microprocessor that comes with dual sensors with real-time water temperature measurements and displays them on an LCD display. In terms of performance, it’s equipped with fast heat technology as well as a safety shut-off setting in case water levels get too low or the temperature is too high. Additionally, it will display a warning each time that the flow is too low.

Keep in mind that it is suitable for aquariums of up to 100 gallons, if you have a larger aquarium, it’d be the smartest to buy two of those heaters. It’s worth noting that these heaters, however, are more expensive compared to the competition, although they deliver great value, as well as a five-year warranty for you to use effortlessly.


Precise temperatures, robust design, customizable, safety features, real-time temperature readings.


A little too expensive.

2. Tetra HT Submersible Aquarium Heater – Best budget aquarium heater

  • Price: $
  • Type: Submersible heater
  • Wattage: 50, 100 and 200-watts
  • Warranty: 2 years

Tetra HT Submersible aquarium heaters are some of the most popular in the market, especially because of their extremely approachable price. This submersible heater is equipped with an electronic thermostat, which makes it ideal for smaller tanks. You can choose between 50, 100, and 200-watt heaters, which can work properly in water tanks of up to 30 gallons. You can install it both vertically and horizontally and give it a proper placement anywhere in the water tank.

Because its price is considerably lower compared to the option above, the automatic thermostat maintains a sufficient temperature for fish in different ways. It maintains the tank temperature at 78 degrees Fahrenheit which works perfectly for most of tropical fish. There is also an indicator that lets you know when the heating is activated. For example, the LED light will turn green when the temperature that is desired is reached, while the red temperature indicates that the tank and water are heating up.

Given its features, one would wish to be able to manually adjust the temperature and prevent paranoia by worrying whether fish is overheated or not sufficiently warm. Also, those who can’t afford stronger heater will have to purchase two of them to use in aquariums larger than 30 gallons.


Electronic thermostat, LED indicators, fully submersible, minimalistic design, adjustable, various wattage options


Not adjustable temperature, not for larger tanks.

3. Cobalt Aquatics Flat Neo-Therm Heater – Best overall aquarium heater

  • Price: $$
  • Type: Submersible
  • Wattage: 25, 50, 75, 100, 150, 200W
  • Warranty: 3 years

If you’re looking for a fully submersible aquarium heater with outstanding design, features, and performance, you’ve come to the right place. Cobalt Aquatics Flat Neo-Therm heater is efficient and provides both aquarium and terrarium heating. It’s equipped with a reversible bracket which allows the heater to be located both inwards and outwards. It comes in different wattages and sizes which should properly accompany any type of tank that you may be using.

When it comes to the temperature measurements, it is equipped with a touch system that accurately displays the temperature changes with 0.5 degrees Fahrenheit temperature increment. You can heat the tank from 66 to 99 degrees Fahrenheit without worrying about malfunction as the system is equipped with integrated thermal protection, which prevents overheating. The neo-therm feature allows it to automatically shut down if some other malfunction shows up.

It’s also worth noting that it boasts robust resin and thermoplastic design with shatterproof sturdiness. It also comes with a three-year warranty in case something goes wrong with it.


Customizable, adjustable temperature, protection features, sturdy design.


Relatively more expensive than the competition.

4. Hydor In-Line External Aquarium Heater

  • Price: $$
  • Type: In-line
  • Wattage: 200, 300-watts
  • Warranty: 1 year

When it comes to the larger aquariums, it’s best to pick the in-line type aquariums, which are great for larger tanks. Hydor external aquarium heater provides great features in terms of consistency, quality, and reliability. You can hook it to the filter line of the aquarium to heat the water before it actually enters the tank. Additionally, this unit is great if you’re working with both freshwater and saltwater fish and is extremely easy to use.

In terms of features, the Hydor In-Line External Aquarium is equipped with various features that keep it ahead of its competition. For example, there is a reliable PTC technology that helps you rest your mind at peace by not overheating and maintaining stable temperature which provides comfort to the fish. The heater is designed to be installed in the vertical position, although it’s extremely easy to be performed.

It’s extremely easy to use, although it can be hard to adjust. There’s no visible temperature display, although temperature adjusting is fairly easy. If you have a large terrarium, this is a great investment to keep fish warm and lively.


Easy to hook, suitable for both freshwater and saltwater applications, prevent heating.


No temperature display, can’t be mounted horizontally, short warranty.

5. EHEIM Jager Aquarium Thermostat Heater

  • Price: $
  • Type: Submersible
  • Wattage: 100-watts
  • Warranty: 3 years

EHEIM Jager Aquarium Thermostat Heater is one of the best budget-related aquarium heaters, and it’s great for tropical fish. It’s a fully submersible aquarium heater that is loaded with a plethora of features a medium aquarium owner could be looking for. It’s made of a shatter-proof and temperature shock resistant glass, which contributes to its sturdiness and reliability. You can place it both vertically and horizontally, although vertical positioning provides better access to the controls.

Also, there are several protection features that this tank heater offers. One of them is the automatic shut off process in case the water levels in the tank suddenly go too low, while another feature makes it shock-proof, meaning it won’t cause some kind of electronic disaster. There is also an off/on indicator that shows whether it’s heating the water or being in standby. There is also a TruTemp dial, which helps users adjust the temperature using the 0.5 degrees increment. It’s worth noting that there is no LED or LCD display to support smart temperature monitoring. Also, the calibration process can be extremely exhausting and take a few days.


Sturdy design, a lot of safety features, affordable, 0.5-degree increment.


Too long to be mounted horizontally, the calibration process takes long

6. Aquatop Quartz Glass Submersible Heaters

  • Price: $
  • Type: Submersible
  • Wattage: 50, 300-watt
  • Warranty: one year

Aquatop’s Quartz Glass Submersible heater may be one of the aquarium heaters you could be looking for if you’re looking for a simple heater that gets the job done. It’s fully submersible and offers wattage from 50 to 300 watts. You can submerge it anywhere in the aquarium and have it monitor the temperature from 68 degrees Fahrenheit to 93 degrees Fahrenheit.

The temperature is kept consistent thanks to the automatic temperature adjustment tool, which adjusts the temperature when it gets high enough and automatically turns off when the water isn’t warm enough. The thermometer is easy to read, although it’d be more appreciated if it’d have an LCD screen to monitor its readings in a more user-friendly way. Another good thing about this aquarium is that it’s good for both tropical fish, as well as freshwater and saltwater use.

All in all, it looks premium and durable, which means you don’t have to worry about unexpected expenses. The bad part is that the readings aren’t always 100% precise, although they shouldn’t compromise the safety of fish in the aquarium.


Adjustable temperature, fully submersible, durable construction, suitable for both salty and freshwater.


Not 100% precise temperature readings.

7. Marineland Precision Heater

  • Price: $
  • Type: Submersible
  • Wattage: 50-400-watts
  • Warranty: Lifetime warranty

When it comes to the best aquarium heaters, you won’t make a mistake if you have a small to the medium aquarium and are looking for a durable and affordable option. Another good thing is that it doesn’t require too much space. There is total of 8 sizes accompanying this aquarium heater, going down from 50 watts for 10-gallon aquariums up to 400 watts, which should suffice terrariums larger than 30 gallons of water. Its affordable price made it possible for you to purchase more than one aquarium heater and set them to work simultaneously.

This aquarium helps you easily set the desired temperature within a one-degree increment. Additionally, there is a thermal switch that turns off the heater when the temperature is reached and again turns on when the temperature drops. There is also a special heating element that contributes to premium heat transfer and makes it more durable.

Unfortunately, there are a few drawbacks. For example, the glass may not be completely shatterproof, and temperature readings may not always be absolutely accurate.


It can heat large amounts of water, one-degree increment, easy to mount, easy to use


Not completely shatterproof, not accurate readings.

8. Aqueon Submersible Aquarium

  • Price: $
  • Type: Submersible
  • Wattage: 50,100, 150-watts
  • Warranty: Limited lifetime warranty

This submersible aquarium heater is the best affordable market can offer and is available in a variety of sizes and wattages. It boasts the temperature range of between 68 degrees Fahrenheit to 88 degrees Fahrenheit, with a temperature increment of one degree. When the temperature is lower than it is designed to be, the heater is automatically turned on, which it shows on its LED indicator so that you know that it’s running.

It is equipped with a shatter-resistant build, which allows it to fully submerge and remain durable for years. It’s easy to place the heater near the water filter so that the water is warmed faster and provides even heat distribution. There’s also a lifetime warranty for users that purchase it.


Precise 1-degree increments, LED indicator and screen, shatter-resistant, safety turn off.


Not for large tanks.

9. BOEESPAT Submersible Aquarium Heater

  • Price: $
  • Type: Submersible
  • Wattage: 300 watts
  • Warranty: N/A

If you’re looking for an aquarium heater adjustable for both fresh and saltwater, BOEESPAT submersible aquarium heater is the right choice. It has adjustable water temperature of 60 degrees to 93 degrees Fahrenheit. The aquarium heater is equipped with screen that can automatically detect the current temperature in the aquarium. It is also equipped with explosion-proof, and a thickened quartz glass that is durable.

It is easy to set up and adjust the temperature, and automatic switch device, which helps automatically detect the temperature and adjust it whether it needs to be heated more or turned off.


Fully submersible, easy to adjust the temperature, automatic temperature detection, good for large aquariums, good for both fresh and salt water.


Sort of hard to set up.

10. Mylivell Aquarium Heater

  • Price: $
  • Type: Submersible
  • Wattage: 50, 100, 200, 300-watts
  • Warranty: N/A

Mylivell aquarium heater is the last in our list but not any less important. It boasts a sturdy quartz glass design, which makes it more durable, double seal material, and additional sturdy tweaks to make it last longer. It’s safe to use and even easier to set up in the aquarium.

If setting up temperature is difficult for you, don’t worry. Adjustable temperature is great for automatic temperature detection and determining whether water needs to be warmed more or not. It is also equipped with a display that enables fast and reliable water warming. You can adjust the temperature from 65 to 93 degrees Fahrenheit, which is more than enough for all tropical water fish to enjoy in the aquariums.


Adjustable temperature, fully submersible, automatic detection, durable, affordable


Might take too much space, inaccurate temperature readings

Maintaining the temperature of the aquarium

Maintaining the temperature in the aquarium can be extremely difficult if you’re experienced and a little less difficult if you’ve already read up on efficient methods and tutorials. It’s also worth noting that how you’ll manage the temperature in the tank also depends on the type of a heater you’ve chosen above.

Immersible heaters are the best when they’re located near the aquarium filter so that as the water gets filtered, it’ll easily reach the maximum temperature that is suitable for that water tank. In-line and in-sump heaters have quite easier placement, meaning you can install it in-line with your filter, as well as the in-sump heater in the sump system.

Submersible heaters have a slightly more different placement compared to the other in the competition. They are designed to be located completely into the water, so you can’t really put them at the top of the tank. You can place it halfway to the bottom of the tank, but still attempt to not have it too far from the filter so that filtered water gets warmer faster. Additionally, it will help the proper distribution of the heat across the tank.

Those who own large aquariums with a lot of fish species, decoration, and space, the smartest idea is to install two smaller heaters that would be located evenly across the aquarium, and as such provide an even distribution of the heat across the aquarium.

Here’s also a few tips on keeping a stable temperature and clean tank so that you’d have an easier time heating up, without causing unnecessary disaster.

  • Clean your heater – Heaters are easy to clean, and because you want to avoid the accumulation of bacteria algae or anything toxic enough to contaminate the water and fish in it, you should consider cleaning it once a month. While at it, it’s important to regularly check if the heater is working properly and avoid malfunction.
  • Place the heater away from the sunlight – The exposure to sunlight can make the heater overheat while placing it near the air vent could make maintaining the temperature extremely difficult.
  • Match the water temperature to the one from the heater – Regular water changes make for the healthy state of the aquarium and will, in turn, provide an even more comfortable environment for fish that are used to the sufficiently hard temperature. As mentioned above, they might have difficulties adjusting to changes, from cold to warm ambient and vice versa.
  • Choose proper lighting – Some lighting system can produce a lot of heat that stacks with the one provided by the aquarium heater and make the fish feel uncomfortable or sick. For example, the most dangerous lights are metal halide lights, and in that case, you may also need to deploy an aquarium chiller or a fan.

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