fish tank heater

Best Fish Tank Heater 2023

Fluval E Electronic Heater

The digital indicator that always displays the current temperature has three unique indicator settings.Expert Reviewer: Jessie Styles

Quick Summary:
The Fluval E Electronic Heater is an absolutely stellar aquarium heater.

When it comes to normalizing your tank’s water temperature, it has all of the features that you’ll need to craft a tropical paradise for your fish. Its only slight drawback is that it’s somewhat expensive compared to classic-style aquarium heaters, but this is clearly because of the device’s rich feature set.

The bottom line is this: if you want to accurately manage the heat level of your tank, this is the best product on the market today.

Selecting a Fish Tank Heater

Tropical fish like blood parrots, sailfins, and glowfish all need warmer tropical-feeling waters to remain healthy. Unlike people, fish are cold-blooded and don’t produce their own body heat; as a result of this, fish are much more reliant on the warmth of their surroundings as they need warm waters to help regulate their body temperatures.

If you’re planning on purchasing tropical fish or fish that rely on warmer water temperature, you must purchase a water heater. Water heaters of the past were glass devices that you could only partially submerge in your aquarium. Today, there are a few great fully submersible devices that deliver a great overall experience for your fish collecting hobby.

As an aquarium hobbyist, I’ve found that the traditional heating system is problematic for my tropical fish. These devices are typically composed of glass and the heat that they generate isn’t the best for my fish who sometimes like to hide around them. Besides, these types almost always lose their ability to adhere to the walls of my aquarium because I am constantly removing it for cleaning, adjustment, etc. The result is an aquarium heater that floats listlessly around my tank, which you might imagine is unfortunate. Fortunately, I’ve recently found an excellent aquarium heater that is widely considered the best on the market today:

Fluval E Electronic Heater

The Fluval E Electronic Heater is one of the best fish tank heaters on the market. It has some excellent features, which will provide a safe, comfortable environment for your tropical fish. This device is a high-tech unit that employs some great internal features that make managing your tank’s temperature a cinch.


Protective Casing: A unique feature of this device is its vented protective plastic casing. As mentioned before, I’ve always disliked some other models of aquarium heater because they have glass surfaces that fish can be burnt by. To avoid this unfortunate situation, Fluval housed this heater in a square housing. You won’t lose water heating and your pets can get as close as they want to the heater.

In addition to this, this feature also greatly benefits the heater because the internal glass has a layer of protection; meaning that you won’t accidentally crack the glass while moving the heater in and out of your tank. Remember, the internal heating elements inside the glass are typically not fully submersible, so getting them wet can pose danger to both you and your fish.

Dual Temperature Sensors

These devices deftly manage the internal temperature of your tank and the water that they are submerged in. Most units utilize a single sensor setup to attain an accurate gauging of the temperature of the water. Unfortunately, this can be a bit of a slow process, so if your water temperature is suboptimal for your tropical fish, a standard unit may take a moment to provide this information.

The Fluval E Electronic Heater, on the other hand, has two distinct temperature sensors that will alert you in real-time if the internal temperature of the tank has reached below the preset warmth. The digital indicator that always displays the current temperature has three unique indicator settings.

  • Blue: Whenever the Fluval E Electronic Heater detects that the temperature has reached a point where it has become too cold for your preset settings, it will shine a bright blue. This coloration is very visible and lets you quickly adjust or address the issue quickly.
  • Green: Green indicates that the tank’s water temperature is currently within the preset limits. Like the blue illumination, this is very clear and easy to quickly get a bead on while you are going about your daily business.
  • Red: As you might expect, red indicates that the water has become too hot compared to your preset settings. While this illumination isn’t quite as bright as the other two indicators, it’s still fairly visible at a glance.
  • Red and Blue: This indicator combination means that the water temperature has been fluctuating dangerously. This can be due to device failure or due to external factors like fish tank placement.

Maximum Warming Capacity

The Fluval E Electronic Heater can quickly warm a relatively large tank. Its maximum warming capacity is 100 gallons with its 300-watt power supply, so if you have a larger tank, you’ll have to seek out a higher wattage device.


As you heat water it naturally evaporates. This can happen at room temperature, so it’s important to replenish your water as the heat caused by this device causes it to evaporate. A great feature for this unit is its watermark. When the water hits this level, you’ll know that it’s a good time to add more water to the tank.

Suction Cup Assembly

As I mentioned earlier, suction cups can be problematic, especially when you are constantly removing them to clean your heater. The Fluval E Electronic Heater does something unique to help you avoid reducing the efficacy of its suction cups: a removable and adjustable assembly.

Positioned along the rear of the unit you’ll find the standard suction cups, but if you look at the side of the Fluval E Electronic Heater, you’ll also notice a squeezable section. When you apply pressure to this area and lift, the whole device will separate from the section containing the suction cups; allowing you to clean the unit without fully removing the suction cups from the wall of your tank.

In addition to this separation function, you can also adjust where the device is mounted on the suction cups so that you can place the fully submersible heater lower or higher in your tank. This is a fairly revolutionary feature that adds to the value of this aquarium heater.

Shut Off Feature

Protecting your pets is at the center of the design philosophy of this device. With protection in mind, if the device heats itself to over 200 degrees Fahrenheit, it will automatically shut off so that it doesn’t pose a danger to your tropical fish.

Digital Display

This device’s digital display also has some unique features that will help you maintain a perfect living environment for your tropical fish. Along with its water temperature readout, which you can preset in ½ degree Fahrenheit increments, the device will also detail the flow status of the tanks water. This is perfect when there is an issue with your filter or if some other mechanical issue has occurred. If there is low flow, a display of LF will display on the digital display.