What is the Best Aquarium Heater in 2021: EHEIM Jager vs. Aqueon pro vs. Fluval E

What is the Best Aquarium Heater in 2021: EHEIM Jager vs. Aqueon pro vs. Fluval E


There are a variety of aquarium equipment brands and tools being sold on the market today. Some of them are essential, while others are just mere accessories. Aside from filters, plants, and gravel, another thing that is considered a requirement for any aquarium is the aquarium heater.

best aquarium heaters

Because the room temperature may rise or drop throughout the day, you need a device that will keep the water at the temperature your fish needs to survive. For this reason, an aquarium heater is a necessity.

It is important to remember that not all brands on the market would be the best option for your aquarium needs. Choosing the wrong aquarium heater can cause serious health consequences to your marine animals, and therefore, it is important to choose the right one.

In order to do that, you should first learn the ideal temperature required for the specific type of fish in your tank. If you have tropical fish, usually the need environment temperature is between 73 to 82 degrees Fahrenheit.

After knowing this necessary information, it’s time to compute the right size of the aquarium heater. Learn how to do it using the guide below.

How to Know the Right Size of Aquarium Heater

The size of a tank is measured by gallons or liters. On the other hand, the size of the aquarium heater is rated by wattage. Usually, if your aquarium is small, you only need one heater, but for larger tanks, you may need two or more to ensure that the temperature is equal throughout the tank.

Another advantage of having two aquarium heaters is when one of them breaks or gets damaged, you still have one working.

According to experts, you will need 5 watts per gallon of water. Simply put, if you have a tank with 20 gallons of water, you would require a 100-watt heater. It’s always better to choose the right size to prevent problems in the future.

Don’t worry. There is no complicated formula to solve the equation. You just have to practice basic math. You just have to know the necessary information to solve the whole equation.

There is also a more advanced formula to determine the exact heater wattage you will need.  The formula is the following: the desired water temperature you want to maintain minus the average temperature of the room your aquarium is located in.

For example, if your desired temperature is 73 degrees and your average temperature is 83 degrees, the heating requirement would be 10 degrees Fahrenheit.

Next, you will have to get an aquarium heater chart. This chart serves as a guide wherein you will see different tank sizes on the left and the average heating requirement on the top.

Using this will help you find the size of the heater you have to buy. For the above example, say you have a 40-gallon tank, the size of your aquarium heater has to be 100 watts.

Different Types of Aquarium Heaters

As with any equipment and technology, there are multiple types to choose from.  It is important to understand the advantages and disadvantages of all types to choose the right style for your needs.

Submersible Heaters

The unique quality of this type of heater is that it submerges below the water level in your tank. It should remain below the surface, or it risks damaging the heating element. Usually, the submersible heater is placed beneath the filter output, and it heats water as it enters the tank. This way, the heated water circulates within the tank, maintaining the right temperature. Some brands come with a thermometer and have a built-in thermostat, which allows you to set the temperature at your convenience.

Hanging Heaters

Unlike submersible heaters, this type of heater allows you to hang or attach it on the side of the tank. The heating element has to be inside the aquarium in order to function. The buttons for controlling the heating apparatus are on the part that sits outside the tank.

Just like a submersible heater, this type of heater works well when submerged in the water. In other words, when using the hanging heaters, make sure that the water level is higher than the heating apparatus to avoid damage.

External or Inline Heaters

This kind of heater is placed completely outside the tank. It is attached downstream from the water pump, heating water before it enters the aquarium environment. It is similar to a thermofilter, where the water that passes through the filter is heated.

You are able to control the temperature by adjusting the controls found on top of the filter canister. The external or inline heaters are great for protecting your plants and fish in the tank that might come in contact with the heater. According to some users of this tank heater, they are more accurate and safer than the others.

The three types of heaters mentioned above are just a few of the types of heaters you will find on the market. Most brands vary in the materials used to cover or protect the heating element submerged in the water. Such types include glass tube aquarium heater, Titanium heater, and electronic heater.

General Steps in Installing an Aquarium Heater

Once you know the right size and type heater you have to buy, you must install it and check its performance daily. There are specific instructions manufacturers recommend that you follow carefully in order to install it correctly. One important precautionary measure is to never change or install the heater with the fish in the tank.

The following steps are general rules in installing a submersible heater.

  1. Read the manual provided by the manufacturer and check if the heater is fully submersible. Also, make sure that your unit is intact with no signs of exposed wires or damage.
  2. Following the instructions from the manual, attach the heater to the suction cups. Depending on the brand, the suction cups may adhere to the side or the bottom of the tank. Either way, make sure to find a location where the plants and fish do not come in contact with the heater.
  3. Do not turn the unit on after attaching it. Wait for 15 to 30 minutes, allowing the heater to adjust to any temperature change.
  4. Attach the thermometer or temperature gauge opposite the heater.
  5. Turn on the aquarium heater after 15 to 30 minutes. Then, use a thermostat to set your desired temperature for the tank.
  6. Wait 24 hours before putting the fish into the tank. This is to allow the heater and water to obtain similar temperatures slowly. You should check it every 4 or 6 hours to see if you need to adjust your thermostat to reach the desired temperature.

The following products are just some of the great brands you will find on the market. They are some of the top picks according to several reviews and recommendations.

Aqueon Adjustable Pro Aquarium Heater Review

aqueon adjustable pro aquarium heater

This fully submersible heater is available at 50 to 250 wattages for aquariums between 20 and 90 gallons. Aside from its simplicity to install, it is also easy to use.

The suction cups can adhere to glass or acrylic tanks while the unit can be positioned horizontally or vertically, accommodating whatever your tank needs. The dial is placed on top of the unit so you can adjust the temperature even if it is in use.

Aside from this, the dial is also easy to read, so you can always set the heating requirement right. According to the manufacturer, the electronic thermostat is reliable with temperature settings ranging from 68 to 88 degrees Fahrenheit with an accuracy of 1-degree Fahrenheit.

Furthermore, the unit is made of durable thermal plastic, which is safer than those made of glass. The company chose thermal plastic in order to make it shatterproof.

Furthermore, the heater also has automatic features to improve safety. It shuts off when you remove it from the water and restarts when you put it back. There is also a power monitor light that signals when the heater is still adjusting, and when it reaches the desired temperature. Lastly, all buyers are covered by the product’s limited lifetime warranty.


  • Shatterproof and made of durable thermal plastic
  • Can be bought for a wide range of wattages
  • Easy to read and simple to adjust the dial on top of the unit
  • Can be used for fresh and saltwater aquariums
  • Has a power monitor light
  • Safety features include auto-off and auto-on
  • Limited lifetime warranty


  • Issues about defected units
  • Can rust or crack after years of using
  • Burning smell and oily, black residue reported issues.

Eheim Jager Aquarium Thermostat Heater Review

eheim jager aquarium thermostat heater

If you are looking for a simple yet high-quality aquarium heater, fishkeeping enthusiasts have recommended the EHEIM Jager Aquarium Thermostat Heater.

This product is consistently on the top 5 best aquarium heaters because of its features and qualities that last longer than other brands. It’s made of a shock-resistant and shatterproof glass that is durable enough to withstand the environment of a fresh or marine water aquarium.

Whatever size or heating requirement your tank needs, you are sure to find it from EHEIM. You can buy 25 watts to 300 watts for tanks ranging between 7 to 264 gallons. Also, the temperature is adjustable from 64 to 93 degrees Fahrenheit with 0.5-degree Fahrenheit accuracy. In terms of ease of use, the dial is simple, allowing you to set the temperature with ease.

Although the design of the product is typical, its features are comparable to the leading brands. The TruTemp feature is responsible for the recalibration of the heater so as to maintain a precise temperature.

In addition, the thermo-safety control automatically shuts the heater off when the water level is too low, or you remove it out of the tank. There is also an on and off light indicator to further help you monitor the heater.

Once you set the temperature and turn the heater on, the light will also switch on. Furthermore, for all your concerns about the defective unit, you can always make use of the included 3-year limited warranty.


  • Comes in a variety of wattages
  • Simple and durable design
  • Has an on/off monitoring indicator
  • Features a TruTemp system
  • 3-year warranty
  • Easy to use
  • Thermo-safety feature


  • Overheating problems
  • Issues on defective units
  • Sometimes the TruTemp system fails.

Fluval E Electronic Heater Review

fluval e electronic heater

If you prefer to use an electronic heater for your aquarium, there is no other brand than the Fluval E Electronic Heater that can provide you with customer satisfaction. According to many reviews, this product works great because of its advanced technology and safety features.

The dual temperature sensors are accurate, providing the true temperature of water in your tank. If your aquarium requires a heater size between 50 to 300 watts, you are sure to find one under this brand.

The heater size is suitable for a wide range of tank sizes from 15 to 100 gallons. Although installing the unit can be tricky or confusing, you will experience convenience in monitoring the temperature once installed.

The color-coded LCD display is designed to show you the current temperature of the tank. Green means a safe zone or the appropriate temperature you’ve set, blue means the temperature level is low, and red means the temperature level is high.

You can read the temperature in either Fahrenheit or Celsius. As for the safety features, the heater has an integrated fish guard to protect all the fish and plants in your tank.

Meanwhile, the heater automatically shuts off when the water level is too low or when it is not in the tank. In cases when you got a defected unit, you can always make use of the 5-year warranty.


  • Accurate temperature settings with dual temperature sensors
  • Temperature can be set precisely in 0.5-degree increments.
  • Color-coded LCD display
  • Auto shut-off safety feature
  • Integrated fish guard to prevent the fish from getting in contact with the heating element


  • Not advisable to be installed horizontally
  • Installing the unit can be tricky.

Hydor In-Line External Heater Review

hydor in line external heater

The Hydor In-Line External Heater is an excellent choice if you prefer an external heater to a submersible heater. This product is the first external heater on the market with a compact design and runs with exclusive PTC technology.

This technology enables the heater to provide the desired temperature accurately. In fact, it can circulate the heat within the tank steadily within 1 degree of your chosen setting.

Aside from these, it has many safety features to protect it from possible risks such as overheating. These risks are avoided with the auto shut-off feature that is activated when the unit is left running without water flow.

Though it is only available in two sizes, 200 watts and 300 watts, it is equivalent to two stick heaters. If you have a large tank that is up to 120 gallons, one external heater would be enough to maintain the temperature of the water.

The heater works great, whether you have a marine or tropical aquarium. Setting the temperature is also easy using the ergonomic knob. You can adjust it from 65 to 93 degrees Fahrenheit. Lastly, the package comes with a 2-year warranty, promising that the product has a life span of over two years.


  • Provides more space for fish and a more natural environment with no sight of a heater in the tank
  • Works twice than a regular heater
  • Has a 2-year warranty
  • Not prone to overheating
  • Has a compact and durable design


  • Possibilities to leak when the glass tube cracks
  • It only comes in two sizes.

Finnex Digital Heater Controller with Deluxe Titanium Tube Review

finnex digital heater controller with deluxe titanium tube

When it comes to digital heaters, the most frequent name that you will find on the top list is the Finnex Digital Heater Controller. This product comes with an amazing dual relay system that alerts owners about the temperature status of the water in the tank.

There is a LED display that shows the accurate temperature in readable font and format. You may opt to read in Celsius or Fahrenheit. There is also an audio alert protection that uses sound to signal when the temperature is out of the range.

Another feature that people like about this product is its auto shut-off system that prevents the unit from getting damaged when not submerged in the water.

This product also ensures accurate temperatures using the titanium tube. This heating element has a protective guard covering for the safety of all marine inhabitants. Durable and indestructible, you can expect to use this heater for a long time.


  • Dual relay system for easier temperature monitoring
  • Provides accurate and precise temperature
  • Ideal for larger tanks for up to 265 gallons
  • Auto shut-off feature
  • Temperature can be set from 0 – 99 degrees Fahrenheit.
  • Celsius or Fahrenheit options


  • It only comes in three large sizes.
  • Installation can be tricky.
  • Thermostat or cable is short.


All of the products listed are considered to be some of the best aquarium heaters. However, as with any product, there are both advantages and disadvantages to all of them. It is important to choose the right one and make sure you know which would fit your needs the most.

Lastly, make sure to follow the required heater size, the installation instructions from the manufacturer, and the necessary precautionary measures to ensure the safety of your aquarium and marine animals.

VIVOSUN 50W-500W Aquarium Heater Submersible Titanium Fish Tank Heaters Review

When it comes to creating the best possible environment for your fish friends, you should definitely try the VIVOSUN 50W-500W Aquarium Heater Submersible Titanium Fish Tank Heater. This unit offers precise temperature control so you can do your best to make your water inhabitants as comfortable as possible.

This tank heater uses an intelligent IC chip that controls the temperature, and it has a range of 68 to 94 degrees Fahrenheit. This is just perfect for all aquatic creatures.

It is entirely safe as it is made with IP68, as well as a titanium tube material that is designed with anti-corrosion and explosion-proof properties. This makes it safe in case of water shortage, as well as from overheating.

The device is easy to install and it has wide compatibility. You can use it for both freshwater and marine aquariums, glass containers, hydroponic systems, and aquaculture. One heater is suitable for up to 60 gallons aquariums.


  • Precise control over the temperature
  • Compatible with most fish tanks
  • Water shortage and overheat protection
  • You can adjust the temperature without getting your hands wet
  • Easy to set up
  • Great customer service


  • Doesn’t last for a very long time
  • Not too bright

Last Updated: 30th Jan, 2021


  • pets
  • fish
Oğuz Tokatlı

Oğuz Tokatlı

Co-Founder, Editor, Content Creator, and Full Stack Web Developer of ReviewsByPeople.com. I am here to provide you the best content.


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