Best Aquarium Heaters: The Ultimate Guide to Picking the Right One

If you are in a hurry and just want our personal recommendation for the best aquarium heater, we love the Hygger Fast Heating PTC Aquarium Heater.

Aquarium heaters (or even aquarium coolers) are a must-have for fish owners. Without a quality aquarium heater, your fish are going to turn sickly and slow.

And they can even die. And it doesn’t take long for this to happen. They can even freeze to death without the proper temperature from a heater.

See, fish aren’t able to create their own body heat. It’s created by the water they live in.

For example, tropical fish live in warm climates. But if tropical fish live in an aquarium, they don’t have that warm climate to keep their bodies warm and moving.

Which is why aquarium heaters are so important and not something to skip over.

Finding the best aquarium heater is a challenge. There are different types of heaters and each with their special use.

We created this ultimate guide to picking the right aquarium heater for your fish. Plus, we’re going to share the five best aquarium heaters.

In this article we will be reviewing the following aquarium heaters:

How Aquarium Heaters Work 

You might be wondering how aquarium heaters even work. It’s not too different than a space heater or other types of heaters.

Aquarium heaters use electricity to create heat. It only needs to heat the water around it because water absorbs heat.

When it absorbs the heat, it circulates it throughout the rest of the water.

When the heater reaches the set temperature, aquarium heaters turn themselves off. When the temperature of the water drops, the heater starts up again. 

Different Types of Aquarium Heaters 

There are several types of aquarium heaters out there. Which is what makes picking out the right one so difficult.

Each aquarium heater falls into one of two categories. They’re either an interior heater or an exterior heater. And each aquarium heater has its pros and cons.

Immersible Aquarium Heaters 

Immersible Aquarium Heaters


Immersible aquarium heaters are also known as hanging heaters. This is because they hang over the top of the aquarium. So, only the heating element sits in the water to heat it.

These aquarium heaters work well for small freshwater tanks. But we don’t recommend an immersible heater for a saltwater tank.

They aren’t the best heaters to buy. They’re not always reliable, especially when it comes to bigger aquariums. They don’t have enough power to heat such big tanks.

Submersible Aquarium Heaters 

Submersible aquarium heaters are, well, submersible. You can submerge them underwater without any damage to the heater.

You sit one of these heaters next to the inlet of your aquarium’s filter. There’s an LED light at the top of the heater to let you know that it’s on and working.

The heating coil in this heater ensures the temperature is even and the water is always warm.

The downside to submersible heaters is that they use more energy than other heaters.

Substrate Aquarium Heaters 

Substrate aquarium heaters release the heat towards the bottom of the aquarium. They tend to hide out of sight.

They’re perfect for an aquarium with plants. Your plants will get the warmth they need to thrive at the bottom of the aquarium.

But you have to take your entire aquarium apart to install a substrate heater in it. And a substrate heater costs you a pretty penny.

In-Line Aquarium Heaters 

An in-line aquarium heater is always placed between the sump or filter of your tank. In-line heaters are great for fish who don’t like things in their environment.

But if they get damaged, they can leak into the water and get your fish sick.

Filter Aquarium Heaters 

Filter Aquarium Heaters


You place filter aquarium heaters in the filter to your aquarium. They’re heater blocks to be exact. And as the water filters, it disperses heat.

There’s no added equipment to install and they don’t take a large amount of energy. So, your electric bill is safe. 

Different Sizes (Watts) of Aquarium Heaters 

The size of your aquarium heater depends on the size of your tank. There are a few factors you have to take into consideration as well.

But, on average, you need two watts to five watts for every gallon of water you’re heating. That’s not factoring in room temperature.

You subtract the room temperature from the temperature your aquarium needs to be.

Once you know the temperature, you can compare it to the aquarium heater chart that most heaters use.

Aquarium Size/Volume Heat


5 Degrees Celsius

9 Degrees Fahrenheit



10 Degrees Celsius

18 Degrees Fahrenheit



15 Degrees Celsius

27 Degrees Fahrenheit

5 gallons/ 25 liters 25 watts 50 watts 75 watts
10 gallons/ 50 liters 50 watts 75 watts 75 watts
20 gallons/ 75 liters 50 watts 75 watts 150 watts
25 gallons/ 100 liters 75 watts 100 watts 200 watts
40 gallons/ 150 liters 100 watts 150 watts 300 watts
50 gallons/ 200 liters 150 watts 200 watts 2 x 200 watts
65 gallons/ 250 liters 200 watts 250 watts 2 x 250 watts
75 gallons/ 300 liters 250 watts 300 watts 2 x 300 watts

Dual Temperature Sensors for Aquarium Heaters 

Dual Temperature Sensors For Aquarium Heaters


Aquarium heaters with dual temperature sensors are some of the best. They offer real-time readings of the water temperature.

You’ll always have the correct reading whenever you want it. You don’t have to wait for the temperature to pop up or set anything.

Dual temperature sensors deliver you reliability and accuracy. This accuracy is unlike any of the other aquarium heaters. 

Adjustable Temperature for Aquarium Heaters 

Not all aquarium heaters allow you to change up the temperature. The heaters on the cheaper side don’t have this ability.

If your aquarium and fish are simple and small, one of these heaters will work fine.

But most aquarium situations are more complicated, so the needed temperature can change.

So, you need an adjustable aquarium heaters. Always double-check that the heater offers you the ability to adjust the temperature. 

Alerts of Aquarium Heaters 

An alert on your aquarium heater comes in handy. Alerts let you know if you’re aquarium is at the right temperature, if it’s warming up, or even if it shut off.

The nicer aquarium heaters have LCD screens that you can read to determine what’s going on in the tank. The numbers are large so you can read them from a small distance.

Others use light indicators to let you know if it’s warming or at the correct temperature. Each flashing color stands for something different. 

Electricity from Aquarium Heaters 

Aquarium heaters suck up a lot of energy. Some more than others. And you have to take into consideration that the heater is going to be running all day and all night long.

The bigger your aquarium, the more electricity used to keep the water warm. Not to mention, some fish require warmer water. That ups the electricity use even more.

You need to be able to afford the electricity bill you’re going to get in the mail. You don’t want to heat a 120-gallon aquarium of tropical fish if you can’t afford the pricey bill each month. 

Safety of Aquarium Heaters 

Safety Of Aquarium Heaters


Safety is always one of the most important aspects of any product, for both you and your fish.

The better aquarium heaters offer you safety features. There are different ways different brands go about providing their customers with safety.

First, there are heater guards. These guards are like a cage that wraps around the aquarium heater.

This stops your fish from getting stuck behind the heater. With some heaters, fish can run into them and become fried. It all depends on the material used.

Some glass heaters are shatterproof regardless of temperature. Or even a fish running headfirst into it. Others are shock-resistant to protect your fish.

Some brands have technology that can detect if you removed the heater from the water. This technology shuts the heater off right away and by itself.

This prevents you from burning yourself. It also saves it from overuse. It doesn’t need to be on if it’s not doing its’ intended use, heating your aquarium. 

Ease of Maintenance of Aquarium Heaters 

If you plan on having your aquarium heater for a while, you have to take good care of it. Because of this, you want something easy to care for.

Difficult aquarium heaters to care for are frustrating. And you might not have the time to do all the extra work.

Check out the maintenance requirements of an aquarium heater before you buy it. Make sure you can do what it needs.

Maintenance includes cleaning the heater to even re-calibrating it when it needs it. You need to be able to fix it if it breaks or find replacement parts as they wear down.

Every bit of it is something to consider when you’re picking out an aquarium heater. 

Price of Aquarium Heaters 

Price Of Aquarium Heaters


For most of us, the price of an aquarium heater is a huge factor. We don’t have a fortune to spend but we want high-quality care for our fish. And high-quality care includes a high-quality aquarium heater.

It’s lucky that most of the best brands don’t charge you an arm and a leg. They’re affordable and manufacture the best of the best aquarium products.

Make sure to stay in your budget range. Don’t believe that you have to spend more on a pricy fixture to keep your aquarium at the appropriate temperature. 

How to Install an Aquarium Heater 

Installing an aquarium heater doesn’t have to be difficult. But it can be confusing the first time around. And each aquarium heater differs but the basics remain the same.

So, we’re going to go over the steps to installing your aquarium heater and you don’t have to go any further to find out how.

1. The very first thing you need to do is double-check your aquarium heater. Make sure there’s no damage. You need to fix any damage before you begin to install it. A cracked casing, for example, can leave wires exposed in water, that’s going to electrocute either you or your fish.

2. Find the perfect spot for the aquarium heater. Clean the glass on the area that you plan on placing or sticking the aquarium heater.

3. Stick the suction cups to the heater and then stick the heater onto the clean glass. Make sure it’s perfectly positioned either horizontally or vertically. Some heaters have mounting brackets instead. The same idea applies to using brackets. Nothing should be touching the aquarium heater, even if it has a guard.

4. Place the thermostat or thermometer opposite from the heater.

5. Let the aquarium heater sit for about an hour before you move on to the next step.

6. Check the temperature of your aquarium using the thermostat. Make sure the thermostat is working right. Turn on the heater. If it’s adjustable set it to the temperature your water needs to be.

7. Let the heater warm your aquarium up. Check the temperature again after 12 hours to make sure it’s at your desired temperature.

8. Once the temperature is correct, it’s now safe to add all your fish to the aquarium.

9. Even after installation, you need to check the temperature at least once a day if not every few hours. This also gives you the chance to make sure the heater’s working properly as well. 

5 Best Aquarium Heaters 

1. Hygger Fast Heating PTC Aquarium Heater

Hygger Fast Heating PTC Aquarium Heater
Aquarium: Freshwater aquariums 120 to 180 gallons

  • You can fully submerge this Hygger fast-acting aquarium heater.
  • It has a blue LED that anyone can read without straining their eyes. It displays real-time temperature so you’ll always know your water temperature.
  • It has a memory function. And it has overheat protection so it’ll never overheat on you.
  • There’s an IC temp controller. It’s easy to set up and you won’t get your hands wet in the process. You can set it from 70 degrees Fahrenheit to 94 degrees Fahrenheit.
  • This is one of the safest aquarium heaters out there. It’s made with premium PTC and double-sealed by a black protective guard. So, it’s corrosion-resistant and resistant to explosions. It also protects your fish from getting fried from a heating element.
  • It also has Thermo Control. Once it detects it’s out of the water, it shuts down on its’ own.


  • It can be difficult to run the temp controller. It doesn’t always register everyone’s finger when they’re trying to use it.
  • The display screen glitches from time to time according to some customers.
  • It doesn’t work very well while in the vertical position.

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2. Fluval E Series Submersible Electronic Heater 

Aquarium: Aquariums up to 100 gallons

  • The Fluval submersible heater allows you to adjust to the temperature your fish need. You can adjust it by half of a degree each time.
  • There’s an LCD temperature display. You can change it to either Celsius and Fahrenheit in real-time. You can take a peek at it every time you want to check the temperature.
  • The range for the display is 68 degrees Fahrenheit to 93 degrees Fahrenheit.
  • This LCD also changes colors if the temperature of the aquarium isn’t at your pre-set temperature.
  • It has an integrated fish guard. The guard protects fish and invertebrates by making sure they don’t touch the heater element.
  • The glass sleeve is protected from shocks from certain fish.
  • It has microprocessor technology with dual temperature sensors that deliver accurate readings.


  • The temperature reading can be off by a degree or so from time to time.
  • It needs a high water flow to work well.
  • The manual on installation is hard to work with. It needs to be updated in some aspects.

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3. Boxtech Submersible Aquarium Heater 

Boxtech Submersible Aquarium Heater
Aquarium: Aquariums 30 to 80 gallons 

  • The Boxtech aquarium heater can be fully submerged in water.
  • There’s an LED indicator light. When the light is red, it’s on and heating the aquarium.
  • It has an external temperature controller. The controller has a temperature range of 68 degrees Fahrenheit to 90 degrees Fahrenheit. It’s easy to adjust.
  • When the water reaches the desired temperature, it shuts off on its’ own. When the temperature drops, the heater will turn back on to reheat the water.
  • It was designed with safety in mind. It’s made from heat-resistant quartz glass. So, it’s both corrosion-proof and explosion-proof.
  • It has a double-loop circuit design. This design allows a water temperature sensor installed in the IC circuit. This helps prevent any burning or overheating of the aquarium heater.
  • It also has a black guard so your fish won’t swim into it and get overheated.


  • The length of the wire from the heating element to the housing is too long.
  • You need higher water flow to get it to work well.

>>>Check Price<<<


4. Eheim Jager Aquarium Thermostat Heater

Eheim Jager Aquarium Thermostat Heater

Aquarium: Both freshwater and saltwater aquariums

  • The Eheim Jager aquarium heater is submersible without corrosion or other damage.
  • It’s made from shock-resistant and shatterproof glass. The glass is also made to survive both fresh and marine water. It’s protected against drastic temperature changes.
  • The glass jackets make the heating surface larger so the heat is distributed evenly.
  • There’s an On/Off indicator light. You can find out of the heater is on or off by a quick glance.
  • The heater uses a TruTemp dial. The dial re-calibrates the heater so it has an accurate temperature at all times.
  • With the TruTemp dial, you can adjust the temperature. The temperature range is 65 degrees Fahrenheit to 93 degrees Fahrenheit.
  • When the water levels get too low, the heater will shut off.
  • It has Thermo Safety Control. It enables running-dry protection. So, when the heater is removed from the water it shuts off by itself.


  • It’s a super tall heater so it doesn’t fit in all aquariums.
  • It needs a high water flow to work well.
  • Sometimes you need to re-calibrate it more than you should have to.
  • The suction cups used to hold the heater don’t last very long.

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5. Tetra HT Submersible Aquarium Heater With Electronic Thermostat  

Aquarium: Aquariums 2 to 10 gallons, hoods or glass canopies

  • Tetra’s HT submersible aquarium heater can be completely submerged in water.
  • It can be installed both horizontally and vertically in the aquarium. It’s super easy to install. And it’s so small you can hide it.
  • The aquarium heater has a built-in electronic thermostat. It keeps the water of your aquarium at 78 degrees Fahrenheit. This is the perfect temperature for most tropical fish.
  • It has an indicator light so you know the heater is on and warming up the aquarium. It’s red while it’s heating and green when it’s reached the desired temperature.


  • You can’t change the temperature. It only works at 78 degrees Fahrenheit.
  • It’s been known to overheat so it’s important to pay attention to the temperature reading.
  • There have been a few reports of the heater breaking down after a few weeks of use.

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Final Thoughts 

This is an essential accessory for your home aquarium to ensure your water temperature stays consistent. 

The Hygger aquarium heater ticked all the boxes for us and is our recommendation for the best aquarium heater. But your selection will depend on the size of your tank and the temperature that you need to maintain. 

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