The 10 Best Aquarium Heaters

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This wiki has been updated 25 times since it was first published in February of 2017. When it comes to taking care of your fish, environmental maintenance is one of the most important considerations. For that reason, you'll need one of these reliable aquarium heaters to help keep your aquatic companions comfortable. Many function in both fresh and saltwater tanks, will shut off for safety when removed, and will even adjust the water temperature automatically as it fluctuates. When users buy our independently chosen editorial choices, we may earn commissions to help fund the Wiki.

1. Aqqa Fish Tank Heater

2. Finnex Digital

3. Aqueon Pro

Editor's Notes

February 15, 2021:

It wound up being quite a busy round of updates, as many of our previous selections seemed to be no longer available, and therefore needed replacing. The options we removed were the Catalina RF-1000T, Tetra HT, Fluval E Series and Cobalt Aquatics Neo-Therm.

Some of the new choices we added include the Aqqa Fish Tank Heater — an 800-watt model that can handle aquariums as large as 220 gallons, and sports a smart color LED display; the Orlushy Marine — which inconveniences users with its submersible, analog controls, but redeems itself slightly with the inclusion of an external aquarium thermometer; and the Hygger HG-802 — which features an IPX8 element, external controls and a wide temperature-control range of 32 to 104 Fahrenheit.

One thing that surprised us during our research is how behind the times this niche category is in terms of offering models that hook up to Wi-Fi. While it’s certainly true that hobbyists got by for years without it, remote monitoring would still be a nice touch, given how pricey some of these setups are (not to mention that your pets live inside them). If you’re trying to figure out the easiest way to set yourself up with some remote monitoring/control options, the simplest solution might be to hook an element up to a line-voltage temperature controller with Wi-Fi connectivity.

While you're here, you may also be interested in checking out a few more of our aquarium-related rankings. We've got lists for air pumps, skimmers, stands and more.

October 14, 2019:

Whether you’ve got a three-gallon fish tank or one with a capacity of 90 gallons, a reliable aquarium heater will maintain the water’s temperature properly to keep your fish free of the stress associated with frequent temperature changes.

Coming on board today is the Finnex Digital, which is built with safety in mind, with an alarm that will sound if your tank’s water becomes too hot or cold. This powerful choice is suitable for use indoors in your aquarium or outdoors in a backyard pond or a greenhouse. It features a large panel with a user-friendly interface and will retain its settings in the event of a power loss.

Also joining the list is the Hygger Submersible which comes in your choice of 50, 100, or 300 watts, depending on your tank size. It too has several safety features, such as overheat protection and an automatic shutoff if an electrical fault occurs. It can be placed unobtrusively behind plants or rocks, thanks to its small footprint. It’ll maintain your tank’s water in the constant temperature you set, and will reliably stop heating when your water’s temperature is 1.5 to 2 degrees Fahrenheit above or below the set temperature.

Another new addition is the Tetra HD, which comes from a popular name in fish care. This 50-watt, budget-friendly choice is simple to set up and maintain, with a red light indicating it’s heating the water and a green one to let you know it’s on standby. Unlike many others, you can position it either vertically or horizontally, and like the Hygger we added, this one is also easy to hide behind plants, rocks, or other tank décor.

Leaving the selection in today’s update is the JBJ True Temp System, amidst reports the heating element can malfunction and create undesirable temperatures in the tank. The Finnex HMA Series and the Choson Automatic also make departures, due to availability issues.

Special Honors

Inkbird C929A The C929A is a digital temperature controller that issues user notifications via Wi-Fi anytime it runs into any trouble. It uses a dual probe to help ensure good accuracy, and while it doesn't come with a heating element, it does provide an AC outlet capable of feeding up to 1,200 watts of equipment — which means you might be able to get away with using this one to control an old heater with an internal thermostat that's starting to give out.

Aquarium Guardian This nifty unit can monitor the temperature and water level in both freshwater and saltwater tanks, and keeps their owners notified of both via text message, so there's no need to download another app. It isn't a one-stop solution for those looking to fully automate their setups, but it does come with an integrated relay that can either be used to control a heater, lights, or even a pump or solenoid valve to top the tank off when your water level gets low.

4. Hygger Submersible

5. Hydor Original

6. Hygger HG-802

7. Ista In-Line

8. Orlushy Marine

9. Eheim Jager

10. Freesea 25

Ensuring The Longevity Of Your Aquatic Ecosystem

It also works to distribute heat evenly from the bottom of the tank.

Regardless of the species of fish you display in your home, an understanding of their biology is important. So, too, is the realization that, as cold-blooded animals, they are unable to regulate their own body temperatures the way other animals do. For that reason, you'll need a reliable heater to maintain a constant environment in your aquarium for piscine survival and longevity.

The aquarium heater is a device specifically-designed to maintain environmental stability inside a fish tank. Its core heating element is usually enveloped in either glass or ceramic, which is further contained inside a watertight plastic, glass, or steel housing fully-immersed in water. The device is also equipped with an adjustable thermostat responsible for turning the heating element on or off. Traditional aquarium heater thermostats employ bimetallic strips composed of two different metals that expand at different rates as the internal water temperature fluctuates. Other types of thermostats make use of microchips for improved maintenance and accuracy. Most freshwater and marine aquariums are maintained at temperatures between 71 and 88 degrees Fahrenheit.

Aquarium heaters are divided into four main categories, including: immersible, substrate, filter, and submersible varieties. As one of the least expensive options, the immersible heater regulates temperature by means of a control pad located above the water line. This placement makes it less efficient than other heater types, especially when it comes to heating large aquariums. It is also easy to break should it fall into the water, hence its low degree of popularity for mainstream use.

The substrate heater is not typically visible inside the aquarium and, instead, lies below the gravel normally present at the bottom of the tank. This heater is especially useful for those piscine aficionados interested in growing aquarium plants to create a more natural habitat for their fish. It also works to distribute heat evenly from the bottom of the tank. The disadvantage to substrate heaters is that everything inside the aquarium needs to be removed prior to installation.

Filter heaters minimize the amount of extra equipment needed inside the aquarium. Water is heated as it passes through the filter, making it an efficient option for use in extremely large tanks. Submersible heaters are the most popular and common of all four types, given that they waste very little energy, they can be placed anywhere inside their tanks with suction cups, and they function completely underwater.

Maintaining Balance And Knowledge

Before investing in an aquarium heater, it's important to introduce yourself to all of the requirements and processes involved in maintaining a healthy environment for your aquarium fish. Sustaining aquatic life within a controlled environment, and allowing it to flourish for an extended period of time, requires balance and patience. While it isn't always an easy job, the experience of fishkeeping is definitely a rewarding hobby.

It's also a good idea to ensure the unit has built-in overheat protection, considering that fish are quite sensitive to even minor temperature fluctuations.

Determining the type of heater that works best really depends upon the size of your tank and the types of substrate and objects you plan to place inside it. However, the majority of hobbyists tend to lean more towards the submersible variety because of its efficiency, durability, compact size, ease of installation, and its relatively inexpensive price point.

Make sure to check the rating for the heater in question to determine the size of tank it can support. Some submersible heaters are equipped with integrated memory control functionality, which is designed to maintain a preset temperature for the aquarium in the event of a power outage. It's also a good idea to ensure the unit has built-in overheat protection, considering that fish are quite sensitive to even minor temperature fluctuations. If you do need to adjust the temperature of your aquarium, it's not difficult to find an option with a dedicated control knob for manual adjustments. Depending on the size, shape, and nature of your tank, consider a heater that installs vertically or horizontally and is capable of working in both salt and freshwater environments.

A Brief History Of The Aquarium Heater

Archaeological evidence suggests that fishkeeping dates back to the times of the ancient Sumerians and Egyptians between 5500 and 2500 BCE. For example, the ancient Egyptians considered the fish sacred, even going so far as to worship the Nile Perch among other species. The Roman Empire also maintained rudimentary aquariums for the purpose of piscine consumption.

Records from the Chinese Sung Dynasty suggest that people selectively kept and bred carp for ornamental purposes between 960 and 1279 CE.

By the 1920s, the first tropical fish were being sold in toy stores.

The first practical use of the aquarium heater occurred during the Victorian era in Europe. With the opening of the first public aquarium at the London Zoo in 1853, there was a cultural renaissance of sorts during which people became fascinated with the study of animals and nature. Flames from oil lamps were used to heat fish tanks from below using slate bottoms. With the introduction of electricity into the home, people began to experiment with immersion heaters in glass tubes.

By the 1920s, the first tropical fish were being sold in toy stores. After World War Two, fishkeeping became more of a mainstream hobby accessible to the middle class, thanks to advances in aviation that made it possible to transport a more diverse population of fish species all over the world.

The first reliable submersible electrical heater was invented by Eugen Jager in the 1960s. Jager's innovative design served to eliminate the dangers associated with older, over-the-side type heaters with the use of a borosilicate tube and an integrated bimetallic thermostat. Jager's design was later marketed in the United States during the 1970s. Since that time, the device has become an integral part of the hobbyist's aquarium setup.

Will Rhoda
Last updated by Will Rhoda

After deciding that the pen was mightier than the pliers, Canadian electrical contractor William Rhoda abandoned his career and headed back to college, where he majored in marketing and advertising and won a scholarship along the way to earning a diploma in creative communications. His past career landed him a depth of knowledge in tools and hardware, while his current career schooled him in audio, video and camera equipment. During his leisure time, he’s learned lots about outdoor gear, and years of tiresome backyard maintenance have taught him all about pools and hot tubs. His recreational pursuits include rest, relaxation and revolutionary action, and his roommate’s a hairless cat.

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