Pickmythings.com can help you find the best aquarium heater for your aquarium fish tank if only you can take your time to read this guide and reviews of our top 5 best selected freshwater aquarium heaters today!

If you’re in the fish keeping business or your hobby involves tending to and watching your fish grow and interact in an enclosed are (aquarium); then you should know that having an aquarium heater handy is very important.

Whether kept in fishbowls, aquariums or deep in the sea, fishes do not have the capacity to produce their own heat and therefore depend on external sources for that purpose.


The Best Aquarium Heater: Definition, Guide and Review

Definition of Aquarium Heater

An aquarium heater is simply a device that regulates the temperature of the water in an aquarium. They come in different designs and sizes and ensure that your beloved fishes remain warm and comfortable in all seasons. The major types include:

Submersible aquarium heater: As the name implies, are placed inside the aquarium. They can be placed vertically or horizontally and attached to the back of the aquarium with considerable space away from the gravel. This is to ensure that the fishes don’t get caught in-between and get burnt.

Hanging Aquarium heaters: These kinds are hung on the aquarium (better placed at the back) while a glass tube housing the heating element is put inside the water. These types of heaters are common and inexpensive; however care should be taken to ensure that they remain in a position so that the glass covering on the heater doesn’t get broken and electrocute the fishes.

Substrate heaters: It consists of a coil or network of wires in an insulator and buried in the gravel. The wires/coil produces the heat for the water when the heater is on. It is being related by a thermostat that switches off the heater when the optimal temperature is achieved. These types of heaters are not common and mostly used for planted tanks.

In-line heaters: They are external, built in line with the plumbing finish of the aquarium and require a steady flow of water through the water pump to provide heat for the tank. The water flows out of the tank, through a tube, through the heater and the heated water is returned to the tank.

In-filter heaters: For some larger aquariums that require a steady flow of filtered water in and out of the tank, heating elements are built into the filters and they heat up the water as they flow into the tank.

Review of Top 5 Best Aquarium Heaters

Even though heaters are important for your aquarium, it is wise to control the urge to purchase whatever available heater you can find in the market without adequate information. Consequently, this part of the article takes care of that by giving an in-depth review of five top mini heaters based on product specification and user experience.

1. Aqueon 50W Pro Heater

Aqueon 50W Pro Heater

This fully submersible heater by Aqueon has a thermostat feature that regulates the water temperature in your aquarium. It also has power monitor lights that indicate the activity of the heater.

Product features:

  • Type: Fully submersible.
  • Size (watt): 250.
  • Dimensions: 4 x 19.1 x 2 inches; 12.8 ounces.
  • Water size: Up to 90 gallons.
  • Thermostat feature: Yes (electronic).
  • Aquarium type: For fresh or saltwater aquariums.
  • Warranty: Limited lifetime.
  • Amazon prize: $39.25.
  • Other features: Shatterproof; Power monitor light.
  • The long term durability leaves a lot to be desired as it easily corrodes and rust.
  • Users complained about the number reading on the thermostat not corresponding with water temperature.
  • Users complained of the glass cracking, allowing water in and causing electrocution.
  • User complained of heater not adequately heating up the tank though set temperature.

2. Hydor Submersible Glass Aquarium Heater – Original Theo

Hydor Submersible Glass Aquarium Heater - Original Theo

Built with PTC technology, it is self-acclaimed to be the best shock resistant heater and has a shatter proof glass to that effect. There is also no damage in case of running dry.

Product features:

  • Type: Submersible.
  • Size (watt): 25.
  • Dimensions: 3.5 x 2 x 10 inches.
  • Water size: From 2 gallons.
  • Thermostat feature: Yes. Manual.
  • Aquarium type: For fresh or saltwater aquariums.
  • Warranty: Not specified.
  • Amazon prize: $17.99+.
  • Other features: Comes with suction cups; Graduated scale; shock resistant.
  • Users complained of its inability to heat up to proper temperature.
  • Customers also complained of heater suddenly overheating, refusing to yield to adjusted temperature.
  • Users complained of thermostat malfunctioning and heater temperature fluctuating.
  • Most users complained that it stops working after a year.

3. Tetra HT Submersible Aquarium Heater

Tetra HT Submersible Aquarium Heater

This heater comes with an automatic adjusted thermostat and designed to shut off when electrical shock is detected for your safety. All you have to do is place in the aquarium and plug it in.

Product features:

  • Type: Submersible.
  • Size (watt): 50.
  • Dimensions: 5.2 x 1.6 x 3.5 inches; 8 ounces.
  • Water size: 2 to 10 gallons.
  • Thermostat feature: Electronic thermostat to automatically maintain water at 78° F. No adjustment is required.
  • Aquarium type: For fresh or saltwater aquariums.
  • Warranty: not specified.
  • Amazon prize: $9.99.
  • Other features: Indicator lights.
  • Temperature can’t be increased as it comes pre-set.
  • Most users complained that Stopped working after 2-3 months
  • The light may be deceptive as it may not be heating up as indicated.
  • Users complained that it doesn’t warm a 10-gallon fish tank as specified.

4. Fluval E Electronic Heater

Fluval E Electronic Heater

Fussing about temperature levels in your tank becomes a thing of the past with this electronic heater with sensors and LCD display that shows current water temperature in the tank. It has no bi-metallic points which mean corrosion, rust and wear is prevented.

Product Features:

  • Type: Submersible.
  • Size (watt): 300.
  • Dimensions: 2 x 1 x 14 inches.
  • Water size: 100 gallons.
  • Thermostat feature: Yes. Automatic.
  • Aquarium type: For fresh or saltwater aquariums.
  • Warranty: 5 years.
  • Amazon prize: $46.37.
  • Other features: LCD temperature display; colored display alert systems; integrated fish guard; dual temperate sensors; slim profile mounting bracket; fast heat technology with safety shut-off; Advanced Electronic Circuitry.
  • It is big and requires a lot of air flow to not go into an error mode – (Low flow)
  • It is quite overpriced and fancy
  • Users complained of its inability to fully heat up lower gallon even with the 300-gallon capacity it specified.

5. Aqueon 50W Submersible Aquarium Heater

Aqueon 50W Submersible Aquarium Heater

As a step up from Aqueon 50W Pro Heater, this heater has a variety of accessories to help keep your fish and their aquatic environment clean and healthy. It allows you to set and control the temperature level in your tank and comes with automatic shut-off feature for safety purposes.

Product features:

  • Type: Submersible.
  • Size (watt): 300.
  • Dimensions: 9.6 x 11.4 x 10 inches; 1.9 pounds.
  • Water size: 65- 90 gallons.
  • Thermostat feature: Yes (Manual).
  • Aquarium type: For fresh or saltwater aquariums.
  • Warranty: lifetime warranty.
  • Amazon prize: $26.54.
  • Other features: Power monitor light; Shatter-resistant construction; Automatic safety shut off and overheat protection; 6-Foot power cord; Precise temperature setting to 1-degree F (68-88 degrees F).
  • Customers complained of heater breaking after some month of use.
  • Some Users complained of heater increasing in temperature, different from how it was set
  • It tends to produce a buzzing noise after months of use
  • Some customers also complained of heater showing signs of condensation inside of the tube.

The Best Aquarium Heater Conclusion

This article reviewed five submersible aquarium heaters, each having its specification and criticism. It is hoped that with this provided information, you can make an informed purchase if you are looking for the best aquarium heater today.