Best Aquarium Heater (2022)

Best Aquarium Heater

Fish are a great addition to any home.

They bring in a mixture of vibrant colors and focus to a room, as well as a surprising feeling of comfort too.

They may not be a loving dog or a cuddly cat, but they certainly have their own unique traits.

With the varying seasons, there is a big worry that our water-loving creatures might not get the warmth that they need every day.

This is something that all of us fish owners have to deal with at some point, whether from the very first day of buying a fish, or from when fall finally sets in.

Whilst the temperature of the room can become an issue, an aquarium heater will do the job of keeping the tank at a consistent temperature without the worry that the fish will become too cold.

We have put together the top 5 best aquarium heaters so you do not have to search high and low for the right one.

Plus, we have added a buyer’s guide to help decipher what the key areas are when choosing the right heater. 

1. MarineLand Precision Aquarium Heater

Marineland Precision Heater for Saltwater or Freshwater Aquariums

When it comes to keeping the fish warm, most of the time you just want something simple and easy, rather than a product that is fiddly to set up and work with.

The MarineLand Precision heater was really easy to set up.

It includes a temperature dial that enables you to turn it one degree with every click, making it really precise – though we suppose it is in the name, after-all.

This means it was a lot easier to get the exact temperature needed without having to round any numbers up.

Also, the temperature display is very visible, so it was easy to see exactly what temperature was being put on.

It includes an automatic switch-off for when the temperature reaches the particular number it has been set at.

This was good to have because it meant the fish were not in water that was overheating.

When this happens, the heater switches off and then switches back on again once the temperature of the water starts to cool down.

The mounting bracket meant it was really simple to attach it to the glass of the tank without it damaging the material.

Also, it was easy to check the temperature setting quickly with the top dial view. 

Whilst this heater does a great job, it does take a while to heat up, though this does not seem out of the ordinary for a lot of heater models. 


  • Precision temperature – using the dial you can add 1 Fahrenheit per click
  • Automatic switch-off – stops it from overboiling the water
  • Easy set up – can be used straight away
  • Mounting bracket – makes attaching it to the aquarium easy


  • Takes a while to heat up – but this is not unheard of for a water heater

2. Freesa Aquarium Heater

FREESEA 25 Watt Aquarium Betta Fish Tank Heater with Aquarium Submersible Thermometer

If you can only afford a budget option, then the Freesa is a good choice.

Not only does it work the same as other aquarium heaters, it also does a great job too.

With this aquarium heater came a free thermometer which was handy because it meant it was even easier to keep an eye on the water temperature.

As a rule, you should be checking the temperature of the water every day to make sure the heater has not broken, and that you have it at the correct temperature. 

There is a risk of overheating an aquarium which ultimately will kill the fish, so always start with a lower temperature with a new heater because as odd as it may sound, the temperatures can vary widely.

Once out of the packing, there were a lot of pieces to this heater and it did become slightly fiddly to put together, but once the parts were in place, it was so easy to use. 

Just like with the MarineLand, the Freesa automatically turned off once it hit its target temperature, and then it came back on once the water cooled down.

Whilst it works well, it can be tricky to read the times because they are not specific, and the knob can be difficult to turn.

However, even though these did come up as issues, it did not affect the overall performance. 


  • Budget friendly – a great option if you cannot spend too much money
  • Automatic switch-off – will protect the water from overheating
  • Free thermometer – means you do not have to buy one


  • Can be tricky to use – a few hiccups when it comes to design but it works well

3. Vivosun Aquarium Heater

For something a little more advanced, the Vivosun has more than what you would expect for an aquarium heater.

Not only does it look nice in the tank, it was easy to forget it was there (though you should not) due to it being quieter than other models.

The heater itself has an LED temperature display making it really easy to see once it is in the aquarium.

It meant that one look was simple enough to notice whether it was at the correct temperature or not. 

It was also really straightforward to set up the temperature using the external temperature controller.

Due to it being out of the water, it was safe to say that there were no wet hands!

The heater itself has been highly engineered to be anti-corrosion and anti-explosion, making it extremely safe to use in water.

It is also resistant to any damage whilst in use, alongside built-in overheating and water shortage protections. 

Whilst it does look great, the external temperature controller sits in a weird place along the wire meaning it can be a little fiddly knowing where to put it.

Out of all the problems you can have with technology, it really is not the worst. 


  • Quieter – great for if you do not want too much background noise
  • Precise temperature control – gives it the exact temperature reading that you want
  • LED temperature display – which is easy to see in the water
  • Great design – it looks appealing within the aquarium


  • External temperature control – sits in a funny place on the wire which may cause you to struggle where to put it

4. Tetra HT Submersible Aquarium Heater

Tetra HT Submersible Aquarium Heater With Electronic Thermostat, 50-Watt

Sometimes it is good to just go for something that is basic yet does the job well.

Whilst the Tetra is not the quietest, it is a good heater that works well in an aquarium up to 55 gallons.

When first using this heater, the light was red which indicated that it was heating up the aquarium.

After a few hours, it turned green to show that it had reached the target temperature. 

It was quite slow doing so, but we are yet to find an aquarium heater that heats up the tank fast.

It is likely just to be something that will always take quite a while, so it is worth heating the tank up before you put new fish in if possible.

It has a built-in electronic thermostat that stays at 78 Fahrenheit which is the recommended temperature for tropical fish.

This means absolutely no fiddling with the settings is necessary. 

This also means that this aquarium heater is largely suitable for tropical fish only, so if you need something different temperature-wise, then this is not the heater for you. 

As stated above, if your aquarium is bigger than 55 gallons then unfortunately the Tetra will not be suitable, as they do not go any higher.

There are plenty on this list though that will work efficiently for a bigger aquarium size.


  • Preset to 78 Fahrenheit – no having to change the temperature yourself
  • Easy to use – nothing complicated about using this heater
  • For tropical fish – it is already preset to the ideal temperature to keep this kind of fish


  • Size limitation – can only be used up to a 55 gallon tank. Anything after may change the output of temperature 

5. HiTauing Aquarium Heater

HiTauing Aquarium Heater, 50W/100W/200W/300W/500W Submersible Fish Tank Heater with Over-Temperature Protection and Automatic Power-Off When Leaving Water for Saltwater and Freshwater

The HiTauing aquarium heater is the fastest one to heat up out of all the ones we tried.

Due to the intelligent dual-chip temperature control, it allows for rapid heating and easy accurate temperatures.

The design of the heater is not the prettiest due to it having a shell on it which has holes within it.

This is actually to help disperse the heat more evenly, as well as make the heater more robust.

So, yes it does not look as nice as the Vivosun, but it has been designed this way to make it work more efficiently and be durable.

It has an in-built water sensor which means it automatically stops heating if the water level goes below the top of the heater.

As with all heaters, it needs to be fully submerged in water before it can work.

As for the automatic shut-off, it works really well to turn itself off as the target temperature has been reached.

It then switches itself back on to heat up to the target temperature again if the water has cooled down.

This cycle means that the temperature will always stay consistent within the aquarium. 


  • Rapid heating – so you will not have to wait long for it to reach target temperature
  • Automatic shut-off – to help keep the aquarium at a constant temperature
  • Built-in water sensor – will turn itself off once the water level dips below the top of the heater
  • Accurate temperature control – due to the built-in intelligent dual-chip temperature control system


  • Ugly design – however, it makes it extra efficient due to being able to disperse the heat evenly throughout the aquarium

What To Look For In An Aquarium Heater

Here is the handy buyer’s guide that will help you understand the key areas when it comes to buying a heater for your aquarium.


When you first buy a heater for your aquarium, you need to make sure that you pick one that has the correct wattage for the size of fish tank that you own.

If you get this wrong, you could cause the tank to overheat, or it to stay cold, and we do not want to even think about what will happen to the fish if both of these scenarios occur.

So, it is best to get it right in the first place.

This obviously matters a lot more if your fish survives in a particular temperature. For example, tropical fish will want to be kept warm. 

Even so, it can be difficult to understand, so here is a rough estimation of what it may be, though always refer to any instructions on the heater package or from professional advice.

  • 5-10 gallons – 50 watts
  • 15-20 gallons – 100 watts
  • 24-40 gallons – 150 watts
  • 50-60 gallons – 200 watts
  • 75-100 gallons – 250-300 watts

Automatic Switch-Off

Because a heater is used to keep the tank warm, it needs to know when it gets to a particular temperature.

If it does not, it will overheat the aquarium.

Of course, you will never want this to happen.

Whilst it is common sense to use a thermometer anyway (you will want to keep an eye on the temperature manually), once the water reaches a particular temperature, it should automatically switch-off.

This prevents the water from boiling, and means it will then turn back on once the water has started to cool down again.

This action keeps the temperature consistent.

Whilst this is exactly what you want, do also make sure you check the temperature with a thermometer every day.

This way you will know if the heater has broken, or is not warming the aquarium up enough.

If this is the case, you will need to adjust its temperature higher.


The heater itself is not exactly a small thing and it will be noticeable within a tank.

That is fine, though, as it just shows that you care about the temperature of the home your fish live in.

The area that controls the heater lives outside of water and for good reason.

You do not want to be putting your hands inside the aquarium every time you want to adjust or check something.

Also, it may not be waterproof unlike the heater itself – though most of them are likely to be waterproof seeing as you are dealing with water. 

The heater is placed inside the aquarium, normally via suction cups.

It is an easy way to place onto the side of the tank, as well as remove. It also does not cause any scratching to the material. 

Temperature Control

There are a variety of ways to change the temperature, but the best way is to be able to do it outside of the water using an external piece of equipment that is attached to the heater via a wire. 

Every single heater comes with a way to change its temperature, as you will need to ‘tell’ it what the target temperature is – basically, the temperature it is allowed to heat up to before it switches off.

There are heaters on the market that have extremely precise temperature controls meaning you can change the temperature 1 degree Fahrenheit at a time.

This is particularly useful if you need to be so specific.

Otherwise, you really do not need to be specific and any temperature control will do!

Frequently Asked Questions

How Does An Aquarium Heater Work?

An aquarium heater is used to warm the water up making it a nice environment for the fish to live in.

It does this by using electricity to heat up the water, meaning the temperature of the water will rise.

How Long Should I Keep An Aquarium Heater On?

It all depends on how big the tank is.

Generally, it can take up to 24 or 48 hours to get to a reasonable temperature.

If in doubt, use a thermometer so you do not overheat the water.

Should I Switch The Aquarium Heater Off At Night?

You do not need to turn the heater off.

The only times you may do so is if you are removing the heater from the tank, or are doing a water change. 

To avoid issues, have a thermometer in the tank and always check to see if it is working properly.

You do not want it to be broken, overheating the water or not heating the tank up much at all.

Are Aquarium Heaters Worth Using?

They are, especially if you own tropical fish.

It means you can keep the water at a warmer temperature, even if the room itself is cold.

Usually tropical fish like the temperature of around 78 Fahrenheit. 

Where Is The Best Place To Put A Heater In An Aquarium?

If you are wanting to place a heater within a home aquarium, then place it as close to the maximum water flow as possible.

This could be the outlet or inlet of a filter, or putting it in the stream of the powerhead. 

The idea is to have water directly flowing past where the heater is to help disperse the warm water evenly throughout the tank. 

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