Best Aquarium Heater – Buying Guide and Reviews

A heating system for your tank is essential if you want your fish to thrive.   Fish are ectothermic, which means they’re unable to regulate their body temperature, thus reliant on the environment for the heat their bodies need to survive. So getting the best aquarium heater will keep your fish at the right temperature, reducing their chance of developing illness and increasing their lifespan.

There are many heaters available on the market, and it is straightforward to select anything you can pick and think you are good to go. But there are factors that you have to consider to get the right one for your tank setup. This article will cover the things you must know about aquarium heaters and review our top five favorites to help you with your buying decision.

What are the Benefits of an Aquarium Heater?

Fishes require water temperatures to be consistently between 75° – 80° Fahrenheit. And due to season changes, temperatures can drop below 70° in winter, and in the warmer season, it can exceed 80°. Either way, both are harmful to your fish.

Aquarium heater keeps the water from dropping past a certain temperature level and avoids constant temperature changes. These are easily adjustable to set the temperature to the right level; some are equipped with a separate temperature controller, which is very handy.

What are the Different Types of Aquarium Heaters?

With aquarium heaters, you have several types to choose from and categorized according to where you’re supposed to put them, depending on your needs. If it is your first time owning an aquarium and you don’t know what type to get, here are the heater types you may encounter when shopping.

Hanging / Immersible

This heater hangs on top of the aquarium. Its heating element is inside a glass tube which is put underwater,

It’s one of the most common types, and it’s usually the heater bundled into an aquarium kit for beginners. When it comes to performance, it’s less efficient compared to other types but does provide essential heating.

It’s not ideal for brackish and saltwater setup though, salt can get into the tube that leads to corrosion, and worst an electrical short.


This heater is put directly into the aquarium and is ideal to place next to the filter’s inlet, so it heats the water as it reverses into the aquarium. This heater has a coiled element encased in a glass or solid plastic tube. Rigid plastic is preferable as glass can be prone to cracking if the unit overheats.

It is ideal for a giant aquarium where fish will still have enough space to swim effortlessly despite placing that heater. This heater will help to keep your tank at a more consistent and stable temperature than an immersible one.


Some filters come with a built-in heater which is very convenient, but you’ll need to ensure that the filter keeps the temperature at the level you want. The water is heated up as it passes through the filter. The most common filters to have heaters inbuilt are canisters and sometimes power filters.


This heater is fitted between the filter to heats the water up on the way back to the tank. It is very effective for larger aquariums, although the setup may be more complicated. It prevents any possible contact between the heater and the fish.

This type of heater is a power-efficient option for larger aquariums. It is also ideal if you want to keep larger aggressive fish like some cichlids who are known to fight with the equipment you put inside the tank.


As its name suggests, the in-sump heater is in the sump system itself. It has the same benefits as the in-line type and is designed to be more space-saving so that fish can have more space to swim effortlessly. It is much easier to maintain, too, although the sump takes more space in your room.


This type of heater uses wires as a heating element fixed on the aquarium base buried beneath the gravel. It is ideal for the planted aquarium as the heating process stimulates the growth of plant roots. These are typically not used as the central heater but as an addition to other heaters.

What size of heater do I need for my fish tank?

To know the size of the heater to use is to see the volume of your aquarium. Next, consider the ambient room temperature, then work on how much extra heat is needed to get your desired temperature. Check this heater size table for different tank sizes as your reference.

aquarium heater size table

Best Aquarium Heater Reviewed

The table above compares the most important specs of the top 5 models side by side. Now let’s take a look at each model in more detail.

1. Eheim Jager Aquarium Thermostat Heater

Eheim Jager Aquarium Thermostat Heater

Key Features:

  • Auto turn-off at low water
  • Fully submersible
  • Precise temp control
  • Simple and safe recalibration
  • Long power cord
  • 3-year warranty

The Eheim Jager Aquarium Thermostat Heater is fully submersible and features a shatterproof glass construction. It has different wattage options available that you can choose from 25 W – 300W at such an affordable price point.

It also comes with a thermos safety control feature that, if the water drops at a certain level, it will automatically turn off. Thus, keeping your fishes safe and preventing any issues that could compromise your aquarium.

The setup may require some calibration. If you notice the temperature is running slightly high or low, use the TruTemp dial to precisely recalibrate the heater, you can adjust it from 65° to 93° F.  The unit is quite very long, and it can be a challenge to set horizontally. This unit is ideal for a large aquarium.

2. Cobalt Aquatics Flat Neo-Therm Heater

Cobalt Aquatics Flat Neo-Therm Heater

Key Features:

  • Fully submersible
  • Shatterproof outer casing
  • Adjustable temperature range
  • Compact, Modern Design
  • Easy to set up
  • Easy to read LED display
  • Comes with a 3-year warranty

The Cobalt Aquatics Flat Neo-Therm heater is a submersible heater made of a shatterproof outer layer, known for its very compact and sleek design that doesn’t take much space inside the aquarium. It comes with a lot of options. It has a temperature range of 66 – 96°F, and wattage ranges from 25W to 300W.

It has an integrated thermal protection feature that automatically shuts the heater down before it overheats, which is advantageous. Its one-touch system also guarantees efficiency, and once the temperature is set initially, it will automatically adjust based on room temperature. It deviates from the preset temperature by a difference of  ±.2°F- .5°F.

It is made from quality material, making it very durable and used in freshwater and saltwater tanks. But it’s expensive, though, and comes in smaller wattages. And if you have a larger tank, you may need multiple units.

3. Fluval E Electronic Heater

Fluval E 50-Watt Electronic Heater

Key Features:

  • LCD temperature display
  • Fast heat technology built w/ a safety shut-off
  • Colored display alert system
  • Dual temperature sensors
  • 5-year warranty

The Fluval E is famous for its robust and compact design and affordability. It’s a submersible heater that features a customizable design that you can easily place inside your tank with ease. There’s also an auto shut-off feature and a fish guard safety feature that keeps your fish from getting close to the heater.

This heater has a dual temperature sensor to display real-time and ideal water temperatures ranging from 68°F to 93°F. The temperature display changes color when it varies by +/-2°F or reaches past the preset temperature. The adjustment lever is handy, and you can set the temperature with .5° increment. Wattage options available in 100W, 200W, and 300W that suit a wide range of tank sizes.

Note that you need a decent amount of water flow to reap its full benefits. Also, this heater is ideal for up to 100 gallons aquariums, and if you have a much larger one, you’ll need more than one heater.

With its robust and customizable design, safety features,  precise temperatures, and real-time readings, it undoubtedly appears to most aquarium enthusiasts. And also it comes with a five-year warranty which is a plus.

4. Hygger Titanium Aquarium Heater

Hygger Titanium Aquarium Heater

Key Features:

  • Accurate temperature setting
  • Fully Automatic Control
  • Durable Titanium Tube
  • Digital LED Display
  • Wide Temperature Range
  • Automated shut off system
  • Resistant to corrosion
  • Digital controller claims accuracy of .5°

The Hyggar Titanium aquarium heater is getting more famous for saltwater aquariums and can be used in freshwater aquariums.  It is made of light-weighted titanium metal that gives durability and corrosion resistance quality to the heater. It also features a massive temperature range of 32°F to 104°F and wattage options available in 50W, 100W, 200W, and 500W that suit a wide range of aquarium sizes.

It comes with a thermometer and external temperature controller with an LCD showing real-time and ideal water temperatures. To get accurate temperature readings, make sure to place the heating tube and thermometer probe at different sides of the aquarium. It also features an automatic control system that shuts the heater off whenever it drops below the set temperature.

Its durability, reliability, minimal temperature fluctuation, and ease of use make this heater an excellent choice for freshwater and saltwater aquariums. There’s a minor limitation in mounting options as you cannot place it under the substrate.

5. Aqueon Pro Adjustable Heater

Aqueon Pro Adjustable Heater

Key Features:

  • Automatic shut-off feature
  • Adjustable temperature control dial
  • Fully submersible
  • Shatterproof design
  • Easy to read indicator light
  • Lifetime warranty

The Aqueon Pro is a fully submersible heater built with a non-corrosive shell that makes it ideal for freshwater and saltwater aquariums. Wattage options are available in 50W and 100W and have adjustable temperature control that allows you to set the temperature between the range of 68-88°F, with an electronic thermostat accuracy of ±1°F.

It has an auto shut-off feature that comes in handy to avoid overheating and resets when it cools down. The LED indicator light is always on. It shows red when it’s heating the water and green when at the right temperature.

Its reliable functionality, adjustable thermostat, affordability, and lifetime warranty makes this heater so popular. But do remember that you only get one unit replacement.

We hope this guide provides you with helpful information to get the right aquarium that best suits your needs. Considering what aquarium size you have is your way to finding the best heater. But for beginners, we recommend getting the larger size as the temperature result is slower, giving you time to adjust the temperature if you made a mistake. While on smaller tanks, temperature changes can take effect quickly, and a small incorrect setup on the temperature can be fatal.

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