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The 11 Best Aquarium Heaters To Create A Happy Home

An aquarium heater is a must-have, whether you're setting up your first tank or upgrading to a more modern facility for your existing fish population.

Consider the size of your aquarium, how many fish you plan to keep there, and where you plan to place the heater to determine what is the best option.

Keeping those criteria in mind, we set out to search for the most efficient submersible aquarium heater on the market.

To ensure the health and happiness of your aquatic pets, BestForPets (bestforpets.org) presents the best aquarium heaters to create a happy home on the market today.

Considerations for Purchasing an Aquarium Heater


Submersible fish tank heaters are the norm and should never be used above water. Some of them will even shut off by themselves if the water level drops too low.

Substrate heaters are installed on the tank’s base and are commonly used for heating the soil or gravel upon which reptiles and plants grow.


The standard aquarium heater is a cylindrical rod. Choose one that isn’t any deeper than the water in your tank.


The wattage of a water heater is directly proportional to the amount of water it can heat. An aquarium needs between 2.5 and 5 watts of lighting for every gallon of actual water content.

Two lower-wattage heaters may be better for larger tanks since they can distribute heat more evenly.


A heater with one or two suction cups will allow you to safely connect it to the inside of a glass or plastic tank.


Many heaters have thermometers that can be detached or are incorporated right into the appliance.

These are a pleasant peace of mind that the water temperature in your fish tank is perfect. You can get one separately if your heater doesn’t come with one.

Assuming The Spruce Is Risky.

Anne Fritz, the author of this post, has spent over two years investigating pet supplies on behalf of The Spruce.

She researched the topic by reading testimonials from satisfied customers, articles written by unbiased third parties, and data from official brand websites. A veterinarian, she researched online to find out where various fish species would thrive best.


The FREESEA Aquarium Submersible Heater is our top recommendation for home aquariums up to 10 gallons in size (see it at Amazon). 

It includes a large, easy-to-read LED temperature display that is reasonably priced and reliable. Eheim’s Jager Aquarium Heaters are a great option for those with smaller tanks (see at Amazon). The temperature function can be adjusted to work with your tank, and the unit is built to last.

BestForPets (bestforpets.org) hopes you can find the best aquarium heaters to create a happy home for your pet.


For the Win, All Around: FREESEA Submersible Aquarium Heater for Fish Tanks

No need to purchase an additional thermometer because this heater displays the current temperature in a huge, easily readable LED.

What’s more, you can rest easy knowing that the water in your tank is always at the ideal temperature thanks to the heater’s ability to activate automatically if the temperature in the tank falls below the one you’ve selected.

In order to give you more options when setting up your aquarium, this heater may be mounted on either the side or the bottom of the tank.

This underwater thermometer is suitable for both saltwater and freshwater fish tanks, with a temperature range of 59 to 94 degrees Fahrenheit.

The heating feature turns on and off mechanically as needed; you may adjust the temperature using a touch button on the cable.

The heater’s cord isn’t watertight, so don’t put it in the pool with you. It is recommended that you wait at least 10 minutes after turning off the heater before cleaning or replacing the water in the fish tank.


The Orlushy 500W Submersible Aquarium Heater is Ideal for Giant Aquariums

With its 500 watts of power, this heater can maintain a 100-gallon tank at a 68 to 89 degree Fahrenheit temperature range, which is ideal for fish. It has a length of 13 inches and must be completely immersed in water to function.

Experts recommend using two smaller heaters (placed on opposing sides of the tank) if your tank isn’t too deep so that the heat is distributed more uniformly.

The heater has a dial to adjust the temperature and a glowing red light to show when it is on and providing the desired warmth. The cord is quite long at 6 feet.


The Eheim Jager Aquarium Thermostat Heater Is the Best Option for Small Aquariums

This classic aquarium heater from German manufacturer Eheim is suitable for aquariums up to 10 gallons in size and will maintain water temperatures between 65 and 93 degrees, ideal for fish and other aquatic life.

If you find that your heater is consistently too hot or too cold, you can adjust it precisely by turning the TruTemp dial by a maximum of 8 degrees.

An integrated thermal safety switch will switch it off when the water in the tank becomes too low. The heater’s double suction cups ensure a secure hold on your tank’s side. This glass can withstand impacts and won’t break easily.


Marina Betta Submersible Aquarium Heater is Ideal for Betta Fish

It’s been made with betta fish in mind, so the heater is thin and flat and uses only 8 watts. It maintains a water temperature of 75 to 85 degrees Fahrenheit and can be used in tanks made of plastic or glass up to a capacity of 1.5 gallons. (Betta fish, according to the experts, do best in water between 75 and 80 degrees.)

The red light on this heater lets you know it’s on, but there is no on/off control. Before you clean the tank or replace the water, disconnect the unit and let it cool for 15 minutes.

You’ll appreciate the outside polymer’s durability when it comes time to clean it, since it will hold up longer than regular glass.


Most Worthwhile Investment: Innovative Marine Helio PTC 200 Watt Aquarium Heater with Digital Timer

It’s true that this heater is more expensive than others, but those who are serious about their home marine reef aquariums feel the added features are well worth the money.

As a first step, it features two 100-watt heaters, which can adequately warm a 50-gallon tank. The method relies on a set of solid-state ceramic chips known as Positive Temperature Coefficient (PTC) to do this.

As a result, the device can heat up rapidly, distribute heat uniformly so there are no hot patches, and maintain a safe operating temperature. Once it reaches a certain temperature, it will automatically shut off.

If there are any sudden shifts in temperature, the Smart Controller will sound an alarm. This heater is more efficient than others of its kind, which is a plus.


Hygger’s Fast Heating Titanium Aquarium Heater Is The Top Pick Among Electronics

The huge, simple-to-read LED temperature indicator ensures that your fish will always be comfortable. The superior titanium used in the construction of the submersible heater is double sealed by a black protective guard, ensuring that your fish will not be harmed in the unlikely event that they come into contact with it.

It has a built-in shutoff feature that activates if the water level in the tank drops too low, protecting the unit from running dry. With the external temperature control, you can make the necessary adjustments without getting your hands wet.

The 500-watt unit is designed for aquariums between 60 and 120 gallons in capacity, making it suitable for both freshwater and saltwater environments.


The AIICIOO Reptile Heating Pad Under-Tank Heater is the Best Option

Under tank heaters that don’t require water are useful for keeping reptiles, amphibians, and amphibians at the right temperature in an aquarium.

PVC material acts as insulation, keeping the pad and your tank warmer for longer, while a nichrome heating wire provides rapid, consistent, and uniform heating.

You can attach this heater to the edge of your tank, and it’s ideal for hermit crabs and other species that like cooler temperatures. To regulate the pad’s precise temperature, a thermostat is sold separately.

Fish-Related Questions and Answers

Heated Tanks

You probably have some questions if you’ve never bought an aquarium heater before. While it would be awesome if we could read your mind, there are a few inquiries we get frequently.

These are the most often asked questions, and we have provided answers to them below. Feel free to contact us personally if you have any more inquiries.

What Number of Heaters Should I Buy?

Since there is so much conflicting data available, this is a common inquiry.

Every aquarium heater product page will tell you that it can successfully heat your tank by itself. On the other hand, seasoned aquarists will tell you that investing in a pair of heaters is a must.

In that case, which is it?

This is where we stand:

The water in your aquarium can be warmed by any of the top aquarium heaters without any additional help from you. The makers aren’t engaging in any sort of deceptive marketing.

If at all possible, though, you should purchase two. As a result, it’s simple to maintain a warm water supply no matter the weather.

Because of this, each heater won’t have to work as hard, and if one fails, you still have a fully functional replacement.

If you go this route, double check that the combined power of the heaters you buy is less than the minimum required by the manufacturer for your tank’s volume.

What Do I Need to Do to Get It Started?

Installing an aquarium heater is a lot less complicated than you might assume. The modern heaters are almost ready to use right out of the box, but there are still a few things you should do.

Important: Do all this without any fish in the tank. Some of you may already know this, but it’s important to state for completeness.

  • Verify the satisfactory appearance of all aspects. Make sure it looks good and functions properly with your eyes before you drop any electrically powered objects into your tank. Everything is how it should be, no odd wires are protruding, and everything looks just like it does on the box.
  • Remove any dirt or dust from the glass where you plan to install it. To ensure the suction cups attach securely to the interior of your tank’s glass, you may want to give it a short scrape. As such, it’s important to position the heater close to the filter’s inlet or wherever hot water is being circulated.
  • To properly install the heater, please refer to the supplied instructions. These days, most aquarium heaters (that can be submerged) are installed in the same way. That being said, make sure it’s mounted securely by following the instructions carefully.
  • Don’t rush it; give it a second. You should probably let your fish tank heater adjust for a while before turning it on. Follow the instructions in the booklet since each maker has their own suggested time.
  • Check the temperature. Before you turn on the water, make sure it is at the proper temperature by using a thermometer. This will serve as a starting point from which you can evaluate the performance of your new heating system.
  • Just flip the switch and hang on a sec. Wait about a day after adjusting the heater to the desired temperature for the tank water. After checking that the aquarium heater is functioning properly, you can add the fish.

Is It Possible to Verify Its Optimal Operation?

To quickly address your question, yes, you should use a separate thermometer to confirm that your heater is functioning properly and providing an accurate reading.

For safety’s sake, you should do this regularly. Protecting your aquatic life is easy and won’t take long at all. A few seconds a day spent checking can help alleviate worry (especially when your heater is still on the new side).

Author Image

Dr. Barry Buttler

Dr. Barry Buttler, DVM, MS, DACVIM, is an experienced veterinarian who specializes in the care of small animals, specifically dogs. Dr. Barry K. Buttler is a member of the American Veterinary Medical Association and holds multiple certifications in small animal emergency medicine and geriatric pet health.

Veterinarian (DVM) Dr. Barry Buttler


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