6 Best Aquarium Heaters – Ultimate Review for 2021

This is a review of 6 of the best aquarium heaters.

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Fluval E300 Advanced Electronic Heater, 300-Watt Heater for Aquariums up to 100 Gal., A774

• Aquarium heater with dual temperature sensors provide accurate and real-time water temperatures
• LCD temperature display available in both Fahrenheit and Celsius; with a range of 68 to 93 degrees Fahrenheit
• Fast heat technology built with a safety shut-off and integrated fish guard to protect fish and invertebrates
• Equipped with a slim profile mounting bracket and colored display alert system
• 300-watt heater for freshwater and saltwater aquariums up to 100 gallons with a 5-year warranty

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Last update on 2021-06-29 / Affiliate links / Images from Amazon Product Advertising API

We all want to keep our fish healthy and happy.

That is why we need the best aquarium heater possible.

Your aquarium heater is one of the most important pieces of equipment you will purchase as an aquarium enthusiast, so spending time to research the best heater to fit your fish environment will ensure your money is well-spent.

Without the right heater, you may find that your fish have difficulty in maintaining their body temperature, which can lead to problems with health and reproduction – not something any fish owner wants!

With so many different types, it can be tricky to know which one is right for you.

To save you time, we did the heavy lifting for you and completed extensive research so you can choose the best aquarium heater that is best suited for your personal fish environment.

Here are the reasons we love the Fluval E Electronic Heater (Fluval E200) and think you will too:

• Dual temperature sensors create extreme accuracy in real-time
• Digital (LCD) display for heating mode and standby mode
• Heat range of 68 to 93 degrees Fahrenheit
• Alerts you if there is a serious temperature problem in your tank
• Has an integrated fish guard to protect your fish from the heating element
• Comes in various sizes of E heaters to meet your aquarium size needs
• 5-year warranty

We know you’re excited to jump into the details about the best heaters so you can pick one out. However, we want to be sure you are getting the one that is the most suitable for your aquarium life.

For that reason, we have included the information you need to make the best selection.

If you have already completed your research and you are here to simply read our recommendations, here are the other heaters we have included.

You can check the price and details on Amazon by clicking on the heater you are interested in or hop on down on the page a bit and you will find the full details of each review.

• Cobalt Aquatics Flat Neo-Therm Heater

• Hygger 200W Digital Quartz Aquarium Heater

• Hydor In-Line External Heater

• Fluval M200 Submersible Heater

• Aqueon Pro Adjustable Heater

• EHEIM Jager Aquarium Thermostat Heater

It is important that you use an aquarium heater to maintain the proper temperature range for your fish, considering your fish need help to regulate their body heat.

Before you start comparing the best aquarium heaters to find one suitable for your fish tank, be sure the water temperature needs to be regulated.

This will depend on the type of fish you plan to put in your aquarium.

For example, white cloud mountain minnows, dwarf freshwater shrimp, and goldfish (just to mention a few) are perfectly happy in a tank without a heater because they are considered cold-water fish. They easily thrive living in a tank of room temperature water.

However, this is not common for most fish that are popular for aquarium enthusiasts. The typical aquarium fish are tropical fish that need water temperatures ranging from 75-85 degrees F (24-28 degrees C).

If they are put into a water temperature range less than this, it is too cold and they will not survive.

For these reasons, you need to have a plan in place for the kind of fish you will be putting into your aquarium so you know if you will need to purchase a fish tank heater to maintain the proper water temperature for them.

While things such as a year warranty or lifetime warranty are important, it is more important to get a heater that will give your fish a happy and healthy environment to live in.

The most common problem fish pet owners have with their new aquariums is getting them too cold because they didn’t think about how many watts were needed and what size heater was appropriate before purchasing one.

When reviewing the best aquarium heaters, it is important to understand the details so you make the best decision.

The first step is to understand how the wattage of the heater impacts the water temperature based on aquarium volume (size.)

Wattage in Relation to Aquarium Volume (size)

Choosing the right size heater is the first step in selecting the best aquarium heater for your tank.

Aquarium heaters come with various levels of power. The power levels are defined by wattage, the higher the wattage level the more powerful the heater.

If the heater is not powerful enough, it will have low wattage which could either lead to dangerous water temperatures (hot or cold) in your tank or cause your heater to constantly run and quickly wear out.

If the heater is too large, the high wattage could lead to overheating and an increased chance of the glass cracking, the water overheating, or dangerous swings in the water temperature.

The common rule among aquarists is that the wattage range should be between 2.5 and 5 watts per every 1 gallon of water, with 5W being the recommended wattage as long as you are using an aquarium lid to hold in warmth and prevent evaporation.

More wattage may be necessary depending on how much you need to increase the water temperature.

If you are using two heaters, the total heating capacity of all units should be equivalent to the wattage that is required for the correct temperature.

The chart below provides a great visual you can keep handy as a reference:

What Fish are You Putting in Your Aquarium?

To make the best selection, you also need to know what will be going inside your tank.

If you plan on having plants that require low-light conditions or fish that prefer a warmer water temperature, you need to prepare and purchase the correct heater to meet their survival criteria.

For example, the African Cichlid prefers temperatures between 77°F – 85°F while goldfish can live in water temperature up to 68°F.

These two types of fish would be incompatible with each other so make sure all the fish you will be putting in your aquarium live under similar environmental parameters before you make the purchase.

Using the volume size of your tank, knowing the room temperature where you will put your aquarium, and alongside the above considerations, you are ready to determine what size heater your need.

The final step is determining how many degrees you need to raise your aquarium water temperature above room temperature.

For example, if your tank is 20 gallons and the room temperature it’s in is 70 degrees F (21 degrees C), you need a 60W heater.

However, if the tank water temperature needs to be 75 degrees F in this same room that is 60 degrees F (16 degrees C), a stronger heater would be necessary because this is a much larger gap between your room temperature and aquarium temperature. In this case, a 100W heater would be a much better choice.

Selecting the correct heater is essential, and there are many factors to take into consideration.

It is important to use the correct type of aquarium heater because not all types of fish are the same. For example, some need warmer water than others, and some even require a different temperature range in different seasons.

Before you start narrowing down the aquarium heater to actually make a purchase, you need to determine the style and type of heater you need (or want.)

Choosing the best heater depends on the size of your tank and the species of fish you are keeping, as well as personal preference.

You can choose from an external aquarium heater or a submersible aquarium heater.

External heaters use water from inside the tank as part of their heating process. They typically need more space outside the tank.

Just as the name indicates, submersible heaters sit below the surface. They don’t require any additional room outside of the tank. They are also the most commonly purchased because of their low cost, ease of use, and reliable performance.

The type you choose really depends on what your needs are for your fish and their habitat requirements.

Some people may need more than one kind to provide adequate water temperature throughout the year for different seasons.

Hanging/Immersible Aquarium Heaters

An immersible heater mounts and hangs over the edge of your tank. For this reason, it is often referred to as a ‘hanging’ heater.

The heating element in the immersible aquarium heater is typically encased in a glass tube and sits at the top of the water to heat the tank, applying heat from the top down.

While not the most commonly purchased, this heater is the most commonly used because they are often included in the starter pack box for beginner freshwater tanks.

You’ll need a hole in the hood of your tank to allow this heater to sit over the top of it.

Also, it is important to note this type of heater is usually less efficient but it does provide basic heating. Immersible heaters are not recommended for brackish or saltwater setups.

Submersible Aquarium Heaters

Fully submersible heaters are the most popular when people are ready to replace the typical starter kit heater.

They are placed inside the fish tank under the water surface next to the inlet of the filter, allowing them to quickly and easily regulate the water temperature.

These heaters are popular because they hold a more stable and consistent temperature in the fish tank than the hanging heater.

Another helpful feature on most submersible heaters is they have an LED display so you can visually see the heater is turned on.

Another favorite key feature is their ease in setting up.

The combination of high performance and user-friendliness is what makes them the type of aquarium heaters purchased most often.

In-Line Aquarium Heaters

The in-line heater works differently than either the submersible heater or the immersible heater.

Rather than heating the water inside the tank, the in-line heater is placed in the sump or between the sump and filter. As the water flows by this area, it is heated on the way back to the tank.

Aesthetically speaking, many people love that their tank doesn’t show additional equipment but is instead tidy with their fish as the focal point.

Substrate Aquarium Heaters

These heaters were widely popular in the 90s, typically in tanks loaded with aquarium plants, because they produced a gentle water movement to stimulate the plant roots and initiate quick growth.

Substrate heaters operate by starting the heat at the bottom of the tank and pushing it upward. This is done by installing wires onto the base of your aquarium.

However, they are much less popular today, likely because of the difficult installation coupled with a higher cost to purchase.

Since they can still be found today we included them in the review so you would know what you were up against if you came across one of the few still floating around in the market.

There are some things that should be non-negotiable in your quest to buy a new heater for your fish tank. Safety should definitely be on this list.

Safety features that should be included in your aquarium heater are an automatic shut-off if the temperature gets too high or the water level gets too low.

You should also look for a simple and effective way to monitor the water temperature, like an indicator light signifying if the heater is powered on or off. A heater with an LCD or LED screen you can read is another common way to monitor the water temperature.

The importance of the aquarium heater is one that should be taken seriously by anyone considering purchasing this product.

To provide you with the most accurate and updated information for this review, our research was extremely thorough and time-consuming to ensure we were recommending the best aquarium heaters to you.

This is how we conducted the research:

• Scoured forums and online communities for personal reviews, taking into consideration good reviews, bad reviews, angry reviews, and even reputable and unreputable companies so there were pages of notes on each heater to compile for the final recommendations.
• Dug into the manufacture details for each heater to ensure any advertising information that was not on the manufacture’s website was accurate.
• With our top selections, we sourced online communities and groups to get additional real-life experiences with the heaters from a more personal standpoint.

This stacked information gave us everything we needed to give you the best aquarium heater list possible.

We believe this deep research process is much more beneficial than completing a personal trial of each heater because hundreds of uses in different environments are much better than one short-term use in one environment.

Note: All products were available and details were deemed accurate as taken from each manufacturer at the time of the review.

1. Fluval E200 Electronic Heater

The Fluval E200 Electronic Heater features dual temperature sensors and real-time water temperatures.

The Fluval E Series heaters feature VueTech technology. They monitor your water continuously and house an adjustment level to keep temperature adjustment quick and simple in precise 0.5-degree increments.

It boasts an LCD display for the temperature that shows both Celsius and Fahrenheit. The temperature range is 68 to 93 degrees Fahrenheit.

2. Cobalt Aquatics Flat Neo-Therm Heater

The Cobalt Aquatics Flat Neo-Therm Heater is a fully submersible heater that features a simple-to-use ‘one touch’ control system. It boasts an advanced electronic thermostat with an accuracy rate of +/- 0.5 degrees and a broad temperature range of 66 degrees F to 96 degrees F. Any aquarist will love this wide range because they can fill their tank with pretty much any fish they want.

The design brags a modern look that is sleek and super flat so it takes up little space.

A top feature is a focus on reliability and safety, with the integrated thermal protection circuitry which will shut the heater off before any overheating occurs. The unit is also practically indestructible with the shatterproof outer casing.

3. Hygger 200W Digital Quartz Aquarium Heater

The Hygger 200W Digital Quartz Aquarium Heater features an external LED display thermostat controller and thermometer. It is a submersible heater with a black plastic guard.

The water temperature range for this heater is 61-90 degrees Fahrenheit. If the temperature rises above 97 degrees Fahrenheit there is an auto shut-off.

4. Hydor In-Line External Heater

The Hydor In-Line External Heater works great if your tank is smaller and you prefer the heater to be on the outside.

This heater features Positive Thermal Coefficient technology, exclusive to the brand per the manufacturer, which ensures maximum safety to prevent overheating.

5. Fluval M200 Submersible Heater

The Fluval M200 Heater is a great option for smaller tanks.

It is a simple, easy-to-use heater with fewer bells and whistles than many heaters on the market. However, the reliability is excellent.

6. EHEIM Jager Aquarium Thermostat Heater

The EHEIM Jager Aquarium Thermostat Heater is a fully submersible heater.

It has an automatic shutoff if the water level gets to a dangerous level and a TruTemp dial that recalibrates the heater for top accuracy in regulating water temperature.

How Many Aquarium Heaters do I Need

Whether or not you need two heaters in your aquarium depends on the size, as well as the temperature of the room location where you put it.

If your fish tank requires 200+ watts of heat, purchasing two 100W heaters is better than using one 200W heater.

If a heating element were to malfunction in one, the second heater acts as a backup to prevent the water temperature from falling to a dangerously low level.

On the other hand, if one of the heaters were to overheat, with such a large volume of water it is not likely to be powerful enough to overheat the entire aquarium.

How Do I Make Sure My Heater is Working Correctly

The quickest and surefire way to know if your heater is working properly is by using a thermometer to gauge the water temperature.

Typically, it should be between 76 and 80 degrees Fahrenheit for tropical fish, or 68-72 degrees Fahrenheit for goldfish.

A good way to test this is to place the tip of the thermometer into water that you know is at a lower temperature, then feel along its shaft until it reaches room temperature.

The difference in reading will tell you how close your aquarium’s water temperature is getting to either extreme range before needing adjustment.

How Often do I Need to Check My Aquarium Heater

You should check your aquarium heater and the water temperature every day or two, to make sure they are still running at optimal efficiency.

If you choose an in-line heater that is easy to access, it will be easier for you to monitor its performance than if you have one built into a wall of your tank.

The Fluval E200 is the top pick from the reviews included in this report.

The specifications are good, the overall reviews are good from the aquarist communities in reference to ease in setup, installation, and calibration.

If the size of this Fluval does not fit your aquarium needs, check out the other options by Fluval to see if they have one well-suited for you.