Temperature plays an important role in determining the growth and health of your pet fishes. Buying a fish tank heater is a great way to ensure an ideal, comfy environment for your tiny mates.

We will cover every basic detail about these devices to help you choose the best fish tank heater money can buy. Below we have listed a couple of products that we found better than the rest:

Reviews of the Best Fish Tank Heaters

Aquatop Quartz Glass Submersible Water Heaters (50W-300W)

This product is an ideal suit for both small and big sized fish tank owners. The unit operates at a maximum wattage of 300 which accounts for its quick heating process. The quicker the heating is complete, the more energy you save.

Moving on, Aquatop has used premium insulated glasses to produce double insulation. If you happen to live in a cold region, this is going to benefit your fishes greatly.

Its glass design also makes all the activities visible and cleaning super-easy. We tested the 40-gallon version of this model, and it worked seamlessly on a standard household outlet of 110/120V.

It is essential to submerge the heater to the marked line to get an accurate reading of the temperature. Once set, you can adjust the temperature effortlessly with the temperature adjustment knob.


  •    Hassle-free setup.
  •    Easy to clean up.
  •    Energy-efficient.
  •    Superior performance for such a reasonably priced appliance.
  •    Available in various sizes.


  •    Takes time to cool off after turning off the switch.
  •    Won’t provide an accurate read-out of the temperature until submerged correctly.


Aqueon 50W Submersible Aquarium Heater

This one too comes in various sizes and wattages, leaving the customers with enough options to choose from.

One thing we want to warn you before you seal the deal is that it is a very powerful heater. The water gets heated very quickly even at the lowest setting, so be careful not to turn it up too high unless the ambient is really cold.

However, it does feature an overheating protection and auto shut-off feature to keep nightmare scenarios at bay.

If you own two fish tanks, one saltwater, and one freshwater, Aqueon saves you the money of buying two separate heaters. Isn’t that cool?

The manually adjustable temperature knob makes regulating the desired water temperature easy- peasy.

Nonetheless, we did encounter some issues with the heat setting. If you crank up the temperature to 70 degrees F, it shows 75 degrees F. However, unless you’re just too fussy about the thermometer accuracy, you can just put the temperature 3-5 degrees below the level.


  •    Overheating protection.
  •    Quick heating action.
  •    Highly durable of taken care of and used properly.
  •    Suitable for both salt and fresh water tanks.


  •    The thermometer in the heater is slightly problematic.


Hydor Submersible Glass Aquarium Heater- Original Theo

Accidentally dropping a fragile glass heater on the floor is quite human, isn’t it? Thankfully enough, this particular model from Hydor is made of a shatter-proof glass.

If you’re one of those fastidious species of fish lovers who want everything pitch-perfect, the temperature control of this unit should impress you. The heater comprises a graduated scale, allowing you to set and maintain the ideal temperature for your fish buddies.

Given its 2 gallons and up capacity, it renders itself as the best fish tank for bettas. I had previously used this model in my betta fish tank for 7 months straight. Its automatic temperature adjustment feature just makes your life easier.


  •    A befitting equipment for betta fish tanks.
  •    Fits snugly even in small back compartments with the help of suction cup holders.
  •    The in-built thermostat keeps the temperature at the desired level 24/7.


  •    A very low wattage.


EHEIM Jager Aquarium Thermostat Heater

This advanced fish tank thermostat heater uses Thermo safety control to protect the aquarium from running dry. This feature alone gives it a clear edge over many other models in the same range.

If you live in a cold climate and want to pet a betta, this one can be your go-to heater. The thermostat can maintain a warm temperature all day.

We monitored the aquarium for 2 days straight and didn’t find any significant change in the temperature. The unit itself can take care of the heating when you’re not at home.

Another great feature of this heater is its bright and visible numbering on the thermostat dial. Therefore, you don’t have to take the heater out of the tank to set the thermostat. Plus, there’s an amber indicator light to further enhance the visibility.


  •    Precise temperature control.
  •    Excellent at holding up a steady temperature.
  •    The easy temp controls make it suitable for betta fishes.


  •    Hefty price.


Hydor In-Line External Heater- Original ETH

This heater is specially designed for tropical fishes who can survive long enough only in a precisely warm environment. Instead of using standard manual temp control knob, it houses an electronic control for an infallible accuracy.

The 5’8” inch hose might be a little offputting for those who are looking for something more low maintenance. The best part is that you can use it with an external thermostat which lets you tweak the settings remotely.

We really appreciate the option to keep the heater out of the tank. There’s no electric wire or anything to disrupt the view of the aquarium. Even on the coldest days of the year, it can maintain the temp up to 89 degree F.

Fussy about ideal temperature settings for your betta? When it comes to precise heating, we daresay it beats most other high range heaters any day.


  •    Pitch-perfect temperature read-out.
  •    The option to use the heater externally gives the aquarium a spacious look.
  •    Excellent at holding up the desired temperature.


  •    The 5’8” hose requires a certain degree of effort to connect to the fish tank.


Hydor Slim Heater for Bettas, Bowls, and Aquariums

This heater is perhaps the easiest to use fish tank heating device available in the market right now. It works best for small tanks (about 3-5 gallons), especially when the ambient temp is pretty low.

A big thumbs-up for its price. Despite being an incredibly low-budget model, its construction is fairly durable. If you own a fish bowl, the good news for you is that you can place it under the gravel to keep the view unbarred.

On an important note, if the ambient temp of the room is on the higher side, you have to monitor the heater from time to time since it has no auto shut-off option. It could be a bit troublesome when the temp reaches a certain level.


  •    Excellent performance for a cheap heater.
  •    Simple to install.
  •    Good for warming up a small amount of water.


  •    Lack of an automatic shut off feature.
  •    Limited capacity.


Things to Look for While Choosing a Fish Tank Heater

Not all aquarium heaters are created equal. To ensure that the product you’re pinning on is worth the money, look for these features:

  •    Figure out the right heater wattage before buying. While a low wattage like 25 watts will do fine for small heaters, for bigger tanks, you might have to look for units supporting 300 watts. Models like Aquatop Quartz Glass Submersible Water have a wide collection of tanks in various sizes and watts to suit the need of every customer.
  •    Heaters combined with an adjustable thermostat help you keep up a steady temp for a long period.
  •    A thermometer that provides an accurate reading of the temperature.
  •    Safety measurements like overheating protection, auto shut-off button and heater guard.
  •    Choose a fully submersible unit over an immersible one to have a better control over the temperature.
  •    Easy installation process.


Benefits of Buying a Fish Tank Heater

  •    Fish tank heaters help you recreate a perfect habitat for your fishes as well as other living organisms in your aquarium.
  •    Submersible heats distribute the warmth evenly all over the fish tank.
  •    If you pet betta fishes, shrimps, tortoise who thrive well at a particular temperature, buying a tank heater is an absolute necessity.


The Bottom Line

After comparing the features, pro and cons of multiple heaters side by side, we have come to the conclusion that the Aquatop Quartz Glass Submersible Water Heaters provide the best value for money.

If you want something more low-key, the Hydor In-Line External Heater could be the safest bet for you. Its fuss-free set-up and ability to warm up small fish tanks/bowls make it a winner in its league.

Choosing the best fish tank heater takes a while. Read as many reviews as you can, take suggestions from actual customers, apply logic and you’ll surely end up making the right investment.

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Having many years of experience in keeping different types of fishtanks I'm glad to provide valuable content for the beginners and more experienced fishtank keepers.