10 Best Aquarium Heaters for 5 to 100 Gallon Tanks


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Aquarium heaters are a sure-fire way to provide stable water temperature in aquariums that house tropical fish or fish that are sensitive to temperature fluctuations.

There are many types and brands of heaters on the market, and it’s easy to get lost in the process of searching for one, especially if you’re looking to find the best heater for your aquarium.

By reading my article on this topic, you’ll understand the importance and role of a heater, you’ll know what to look for in a heater, and you’ll have an overview of the best aquarium heater options currently available on the market.

Why You Need a Water Heater in Your Fish Tank?

When setting up a fish tank, you’ll need to do your best to recreate the natural environment of your fish, and this includes getting their temperature range just right.

Keeping your fish at lower temperatures than what they’re used to or exposing them temperature fluctuations will bring about health issues or it can even be fatal for them.

An aquarium heater will help you control the temperature of their environment and help stabilize it, so it isn’t affected by fluctuations in air temperature.

Although a heater is not always necessary (e.g. you’re not likely to require a heater if you live in a tropical climate), in areas where outside temperatures fluctuate from seasons to season, an aquarium heater is a must if your fish enjoy warmer water. If you keep guppies or other tropical fish, most likely you will need a heater.

How to Choose a Water Heater for Your Aquarium Size?

The water volume of your aquarium will be the determining factor in choosing the right aquarium heater size.

There are some generally accepted rules like the 5 W per gallon rule, which you can use to approximate the heater size. This table will help you determine the heater size for your aquarium water volume.

Tank Size Heater Wattage
5 Gallon / 20 Liter 25 W
10 Gallon / 40 Liter 50 W
20 Gallon / 80 Liter 100 W
25 Gallon / 95 Liter 125 W
40 Gallon / 150 Liter 200 W
50 Gallon / 190 Liter 250 W
65 Gallon / 250 Liter 2 x 200 W
75 Gallon / 285 Liter 2 x 200 W
80 Gallon / 300 Liter 2 x 300 W
90 Gallon / 340 Liter 2 x 300 W
100 Gallon / 380 Liter 2 x 300 W

The above table should be taken only as a guide and it works only for certain conditions. If the air temperature is 70 °F (21 °C), you will be able to heat the aquarium water to up to 80 °F (27 °C).

You should also pay close attention to the manufacturer’s product description to determine if your heater will be right for your aquarium size.

It’s also a good idea to read up on product reviews to see if the heater you’ve set your eyes on is indeed as strong and efficient as advertised.

Best Aquarium Heaters

Preview Heater Name  
1. Eheim Jager Aquarium Thermostat Heater
2. Fluval E Electronic Heater
3. Cobalt Aquatics Flat Neo-Therm Heater
4. HITOP PTC Submersible Aquarium Heater
5. Aqueon Adjustable Aquarium Heater
6. FREESEA Aquarium Fish Tank Heater
7. Boxtech Submersible Aquarium Heater
8. UPETTOOLS Submersible Aquarium Heater
9. Hygger Titanium Aquarium Heater
10. Hydor Submersible Glass Aquarium Heater

Below you can read a short overview of the best water heaters for aquariums, and the pros and cons of each:

1. Eheim Jager Aquarium Thermostat Heater

This Eheim Jager aquarium heating equipment is a complex and complete system for ensuring proper water temperature for your fish.

The product is available in 8 different wattage sizes for you to pick the size that’s required for the water volume in your aquarium.

The heater is fully submersible and comes with many features that enhance temperature control and safety including:

  • Shock-resistant and shatter-proof glass (suitable for both marine and freshwater applications);
  • TruTemp dial allows you to set the temperature between 65° to 93° F;
  • Running dry protection through the Thermo Safety Control feature;
  • Mounting bracket and suction cup for easy and flexible installation;
  • On/Off indicator light;
  • Heater control accuracy is +/- 0.5° C;
  • 6-foot cord;
  • Simple and safe recalibration.

As I mentioned, the Eheim Jager heater comes with all the basic features you need from a competent aquarium heater.


  • Adjustable temperature;
  • Accurate heater;
  • Easy installation;
  • Running dry protection.


  • Some malfunctions reported by customers, best be used with a temperature controller.


2. Fluval E Electronic Heater

Suitable for aquariums of 30 gallons and more, the Fluval E electronic aquarium heater provides real-time and precise aquarium readings thanks to the dual temperature sensors.

The system features an LCD temperature display, which is available both in Celsius and Fahrenheit as well as a high/low temperature alert feature that will flash in a different color should temperatures fall below or exceed a preset temperature value.

You can fully submerge this Fluval aquarium heater, which is equipped with a slim profile mounting bracket for easy installation. You can mount the heater either horizontally or vertically, however it fits best in your aquarium.

The fish guard protection of the Fluval heater protects your fish when getting into contact with the core of the heater. The protection of the glass sleeve is also useful for protecting the glass itself from larger fish.

Overall, this heater is a good choice for the aquarium sizes it’s rated for. Be sure to mount it at a 45-degree angle to get if working perfectly for you.


  • Dual temperature sensors for accurate temperature reading and control;
  • LCD temperature display;
  • Fish guard protection;
  • High/low temperature alert.


  • It takes a couple of days to heat up the water.


3. Cobalt Aquatics Flat Neo-Therm Heater

I really like the flat design of this submersible heater from Cobalt Aquatics. You can get the heater in six different size configurations for aquariums between 6-55 gallons.

You can install the heater to face inward or outward thanks to the reversible holster/bracket for more control over the installation and positioning.

The temperature can be set between 66-96° F with one touch and the in-built thermostat will keep the temperature at the set level with a temperature variation of +0.5°F.

For easy temperature monitoring, the heater features and LED display, which shows both set temperature and actual temperature at the same time.

Another useful feature of this heater is its built-in automatic shut-off system, which turns off the heater, preventing it from overheating.

A further novelty of the Cobalt Aquatics flat neo-therm heater is the materials it’s made of. The outer casing is a shock-proof, shatter-proof material.

The heater comes with a 3-year warranty, it’s suitable for both freshwater and marine applications.


  • Adjustable temperature;
  • Thermal protection circuitry protects from overheating;
  • 3-year warranty;
  • Shatterproof design;
  • Flat design and easy installation.


  • Requires water flow to work efficiently;
  • Some customers experienced system malfunctions but were covered by 3-year warranty.


4. HITOP PTC Submersible Aquarium Heater

A fully submersible aquarium heater, the HITOP PTC features titanium oxide ceramic heating material, which is safer compared to glass-type heating elements.

The 300 Watt heater is suitable for 60-120 gallon aquariums. The heater element must be completely submerged to avoid damage to the heater.

The heater also features a detachable casing and comes with 4 suction cups for easy fixing.

The heater indicator light takes out the guesswork from knowing when the heater is operating.

The temperature can be adjusted with a knob on top of the heater. Once the preset temperature is reached, the heater shuts off.

My only concern with this heater is the grated design of the detachable cover, which has even bigger holes on the sides, which would allow baby fish or even small adult fish to get into the cover and potentially getting trapped into it, so I don’t recommend it for aquariums with baby fish.

The temperature can be set between 60 and 93 F and the temperature is also displayed in Celsius.

The heater kit comes with a stick-on thermometer for you to monitor temperature changes.


  • Adjustable temperature;
  • Shatter-resistant materials;
  • Easy to install and maintain.


  • Detachable protective cover has large side holes that will let fish get in;
  • No running dry protection.


5. Aqueon Adjustable Aquarium Heater

Available in a variety of different sizes, the Aqueon offers adjustable temperature control (you can set temperature between 68° to 88°F and it features a shatter resistant thermal quartz glass as its heating element.

The Aqueon heater can be installed vertically or horizontally with the suction cups included with the product.

The automatic safety shut off system jumps into action whenever the heater is not fully submerged to protect from overheating and damage.

Another feature worth noting is the power monitor, which is red while the heater is actively heating the water and turns green once the set temperature is reached.

Overall this heater offers good value for money, comes good features that will provide stable temperatures.

Make sure to choose the right wattage for your tank to avoid performance issues.


  • Provides good value for money;
  • Adjustable temperature;
  • Overheat protection;
  • Vertical or horizontal installation;
  • Automatic safety shut off


  • Requires stronger water flow for perfect operation.


6. FREESEA Aquarium Fish Tank Submersible Heater

Available in sizes rated for up to 50 gallon tanks, this aquarium heater should be kept fully submerged to protect from overheating.

This means you should monitor the water level to make sure it stays within the accepted threshold.

The features that make this heater stand out are the following:

  • Small, space-saving design;
  • Real-time LED temperature display;
  • Adjustable temperature between 59 F and 93 F;
  • Equipped with protective plastic casing.

The temperature control box is not water resistant, so make sure to keep it out of the water.

On the other hand, the heater should be submerged as it doesn’t have an overheating shut-off system.

The heater comes in various sizes suitable for 5-50 gallon aquariums.

The automatic constant temperature function shuts off the heater when predefined temperature is reached, but it automatically starts heating when it drops below the set temperature.

The product comes with a 12-month warranty.


  • Adjustable temperature control;
  • Small, compact design;
  • Real-time temperature display.


  • No running dry protection;
  • The holes on the protective casing may make it easy for small fish to get stuck in the coils.


7. Boxtech Submersible Aquarium Heater

Featuring a simple design and installable via suction cups, the Boxtech Submersible Aquarium heater comes in different sizes and works with aquariums up to 80 gallons, therefore, you must choose the correct wattage for the size of your aquarium.

The heater comes with an external temperature controller that stops the heater from heating the aquarium when the set temperature is reached and starts the aquarium when the water temperature falls below the set temperature.

The temperature is adjustable and can be set in the 68ºF-90ºF range. The heater has an explosion-proof design thanks to the heat-resistant milky quartz glass. This coupled with the UL-Approved Power Cord, Controller IPX4, Heater IPX8 make the system shatter-proof and safe.

The Boxtech heater must be submerged into water and installed close to the water intake or next to the water flow. The heater requires horizontal installation via the provided anti-slip silicone suction cups.

Anyone looking for a compact and efficient heater will surely enjoy this Boxtech product provided they choose the right size for their aquarium.


  • Compact and easy to install;
  • Precise with temp variation within 0.5 degrees;
  • Explosion and shatter-proof.


  • No running dry protection.


8. UPETTOOLS Submersible Aquarium Heater

With sizes ranging from 50 Watts to 500 Watts, Upettools submersible aquarium heaters are rated for aquariums between 3-120 gallons.

The heater element is made of durable and explosion proof quartz material. It also features a protective cover. The heater comes with a 1-year warranty.

The dual CPU external temperature control allows you to adjust the temperature and shuts off/turns on the heater depending on temperature changes. There’s also an indicator light on the heater that signals when the heater is on or off.

Temperature range is between 75-89 F. The heater must be installed horizontally, and it should not be buried under gravel or sand. It should have access to water flow.

According to the description of the manufacturer this heater is suitable for both saltwater and freshwater tanks, but it’s not recommended to be used in acrylic or plastic tanks.

The heater comes highly recommended, however, there are a few drawbacks to consider.


  • Good design, easy installation
  • External temperature controller
  • Adjustable heater
  • Automatic shut-off


  • No running dry protection
  • Not suitable for plastic or acrylic tanks
  • Must be installed horizontally (vertical installation not allowed)


9. Hygger Titanium Tube Submersible Pinpoint Aquarium Heater

This Hygger submersible aquarium heater takes things up a notch by rolling out a heater made of heavy-duty, durable titanium without any glass elements whatsoever.

Because of its titanium construction, the heater is corrosion resistant, completely shatterproof, and it can be used in saltwater, freshwater, and reef tanks.

Regarding installation, the heater installs horizontally with the help of suction cups. Ideally, it should be placed near strong water flow, so it heats up the entire aquarium at the same temperature.

While the titanium construction of the heater element is of superior quality, I’d also like to draw attention to the external temperature controller, which is also a great feature of this product.

This external thermostat has a dual LCD display that shows the set temperature and the actual temperature of the water. You can set it to display temperature in either C or F. The red/green light signal shows whether the heater is operating or not.

The temperature range is 32 to 104°F. Control accuracy is +/- 0.5° C. The heater is not suitable for sump tanks, acrylic or plastic tanks, nor can it be used outside.


  • Titanium construction makes this heater a strong and durable option
  • Adjustable temperature
  • Real-time temperature display
  • No glass elements whatsoever


  • Horizontal installation only
  • Costs more than traditional glass or quartz heaters


10. Hydor Submersible Glass Aquarium Heater

This Hydor glass aquarium heater is an affordable heater option that doesn’t come with many bells and whistles but does the job right.

It’s available in 5 sizes (25 to 200 Watts), and it must be installed completely submerged, either vertically or horizontally.

Even though it’s not as feature rich as other heaters in this list, it does have running dry protection, which is useful if you should forget the switch it off during water changes or if water levels in the tank drop.

Temperature can be controlled with the help of a graduated scale that shows temp in F or Celsius. The heater is built for resistance and has a shatter-proof design.

Make sure to pick the right wattage number for the aquarium size you have and monitor the temperature with an external temperature controller as well.


  • Easy to install via suction cups (vertically or horizontally)
  • Adjustable temperature control
  • Affordable


  • Some customers reported issues with the temperature dial being faulty


There are many heater options available on the market, the key is to find the one that meets your requirements and works with the aquarium size you have.

When picking out your heater, I strongly encourage you to read the reviews and see how the heater performs and whether there are any concerns related to their operation and quality.


In your search for the best aquarium heater, I hope my article has provided you with useful information that you can apply right away.

Aquarium heaters all not all made the same, there are many variations in features and operation, so make sure you make an informed decision whenever buying one.

I hope the 10 best aquarium heaters I listed in this article have given you an idea about the features that a heater must have and best way to install them.

Updated: November 27, 2019
Questions & Answers
  1. Hi Fabian! I just got a 5 gallon fish tank with a betta fish for my birthday, but my parents didn’t know that he needs a heater. Now I’m in rush to buy an aquarium heater. Which one do you recommend for a 5 gallon betta fish aquarium?

    1. avatar

      Hey Erica! Happy birth day! 🙂
      For betta fish and 5 gallon aquarium I would suggest to get a small heater, which is 25-50 Watt. You should consider a heater that has a cover, so your fish can’t touch it to avoid any fin or body damage.
      For this purpose I recommend the Cobalt Aquatics or the HITOP heaters which I mentioned above in the article.

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