Pet Gear, Product Reviews

The Best Aquarium Heaters Rated And Reviewed

We’ve reviewed the best aquarium heaters available for 2020.  We looked at a list of features like reliability, value, and ease of installation.  We also made sure the customers who have used these heaters for an extended period of time haven’t had any issues.  We hope to help you find the best aquarium heater to keep your fish as comfortable as possible so they can thrive for years to come.

Fish are sensitive beings and if you keep them as pets, they come with a set of responsibilities. There are various aspects including the breeding cycle, food, temperature, water hygiene and an adaptable environment that have to be taken care of to ensure optimal health of your fish.

Temperature is one of the most important ones of them all. Coldwater fish like goldfish and koi prefer a cooler environment with temperatures around 60°F (15 °C).  Most tropical fish, however, need a warmer temperature range between 75 and 80 °F (24 to 27 °C).

Because different fish species have varying temperature requirements it can be almost impossible to provide the ideal environment for a mixture of coldwater and tropical fish. This limits the types of fish that can be kept in a fish tank together.

If you want a tropical fish tank, you’ll need an aquarium heater to provide the ideal temperature range for these fish species to thrive.

Image Product Details

Hygger Digital Heater
  • Separate Thermostat and Heater
  • Titanium Construction
  • Submersible

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AquaTop Submersible Heater

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What Size Aquarium Heater Do You Need?

Wattage is the main metric that tells you how powerful a heater is.  Larger aquariums need larger heaters.  If the temperature of your house is typically kept very cold you might need a more powerful heater to keep the water temperature up.

It’s better to have too large of a heater than an underpowered heater.  You can always turn a more powerful heater down to put out less wattage and keep the aquarium in the right temperature range.  However, too small of a heater will never be able to get the temperature up.

If you have a large aquarium, you can use multiple heaters.  In this case, you can just add the wattage of the two heaters together to determine the total wattage of your heating system.

A general rule of thumb is to multiply the gallons of the tank by 5 to get the heater wattage.  For example, a 10 gallon tank would need a 50 watt heater.

Best Overall Aquarium Heater

Hygger Digital Aquarium Heater

This combination aquarium heater and thermometer comes in 4 sizes ranging from 50 watts to 500 watts.  The detached thermometer allows you to control the unit based on the temperature on the other side of the tank, instead of using the temperature right next to the heater like most aquarium heaters do.  This allows you to get the water temperature of the entire tank just right so your fish can live their best lives.  The temperature can be adjusted anywhere between 32 to 104 degrees to within half a degree.  The set temperature will stay programmed even if there’s a power outage.

This unit is shatterproof because there’s no glass used in the construction.  The titanium is corrosion proof so it can be used in saltwater tanks.

The heater itself has strong suction cups for easy mounting.  They recommend mounting it horizontally, but it also can be mounted vertically.  The 50 watt version is 8.7″ long, the 100 watt version is 9.8″ long, and the 200 watt version is 10.7″ long.

The power cord is 5.5 feet long so reaching an outlet shouldn’t be a problem.

Tank Size

Recommended Model


5 – 10 Gallons

50 Watt Heater

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10 – 25 Gallons

100 Watt Heater

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25 – 60 Gallons

​​200 Watt Heater​​​

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60 – 120 Gallons

500 Watt Heater

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Remember, if your tank is larger than 120 gallons, you can use two or more heaters.

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Marina Compact Submersible Heater

The Marina C17 Compact Heater lives up to its name.  At n addition to being easy to set up, this fish tank is ideal for use in plastic and glass aquariums, particularly small ones. It is an unbreakable heater that comes as one unit and ideal for fish tanks with a capacity of 3 gallons. It transforms any fish tank into a tropical tank. It is also easy to set up, use, reliable and a great option for those who are keeping fish for the first time.

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AquaTop Submersible Heater

This fully submersible heater offers an easy and effective way to maintain a stable heat environment in large aquariums. It works great for fish tanks of up to 75 gallons and is easy to install with the use of suction cups. Moreover, it features insulated glass construction for added durability efficiency. It can be used for both saltwater and freshwater fish tanks. It is a 300-watts aquarium heater.

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ViaAqua Aquarium Heater

This is one of the latest aquarium heaters from ViaAqua and it features LCD temperature readout, a high tech way that allows you to keep an eye on your fish tank. Its heating element is made from titanium, making it highly durable. It is fully submersible, and the temperature setting is fully adjustable.

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Hydro Mini Heater

The Hydro aquarium heater is a small fish tank heater that works great for small, desktop aquariums. It safely regulates the water temperature to ensure the perfect heat environment for your fish to thrive. It is completely submersible, making it easy to conceal it in your miniature fish tank that has a capacity of 2-5 gallon tanks.

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Fluval Electronic Heater

The Hagen Fluval E Electronic Heater is a technologically advanced heater that resembles a military device. It offers continued regulation of water temperature to ensure survival of your fish. It packs many features including a LCD light that changes color display in case there’s a variation in temperature from the pre-set temperature; and which creates a flashing display if the temperatures change drastically. In addition, it has dual temperature sensors for real time temperature readings. It can be mounted at any angle and the inner shock resistant glass heater core is surrounded by an external guard that protects aquatic life from electrocution.

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ViaAqua Submersible Heater

This is a fully submersible aquarium heater which is available in four wattages. It is made with high quality, break resistant glass and has a built-in thermostat that automatically regulates the water temperature. The temperature readings are usually in red for added visibility while the included suction cups make setting up easy. They can handle fish tanks with capacities of between 13 gallons to 80 gallons.

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Aqueon Pro Aquarium Heater

One of the reasons that make this aquarium heater popular among consumers is its nearly indestructible construction. This is primarily due to its aluminum core which eliminates the need for a glass core, making it stronger and more durable than most aquarium heaters. The electrical thermostat automatically regulates water temperature and turns off when not in water and vice versa when immersed in water. It can be placed horizontally or vertically, and the large control knob allows for easy modification of temperature. Aqueon has great confidence in the quality of their products, which is evident through the lifetime warranty they provide for this heater, which is available from 50 to 250 watts.

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Jager Aquarium Thermostat Heater

This heater is constructed from shatter proof glass for marine or fresh water. It is also shock resistant and heavy for additional strength. It comes with heater feature thermo controls that allow it to turn off automatically when the water levels are too low, and protect against running dry. Its Trump dial automatically regulates the water temperatures while the on and off indicator allows one to monitor things at a glance. It is available from 25 to 300 watts.

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Cobalt Aquarium Heater

Cobalt Aquatics is a brand that is known for its innovative designs and the Neo-Therm is quite the masterpiece. It meets all of the criteria for a good aquarium heater and then some. For instance, it comes with thermal protection circuitry as well as shatter proof glass so you never have to worry about cracked glass. Installation is very simple and the One Touch system allows you to set the preferred temperature. The heater can maintain the water temperature within half a degree.


How do i know if my aquarium heater is working?

An aquarium heater will take a while to heat the entire tank.  To monitor the temperature, use an aquarium thermometer.  Place the thermometer in the aquarium but not right next to the heater.  You want to measure the average temperature in the tank, not the warmer water right next to the heater.

If the heater isn’t keeping the temperature right where you want it, you can adjust the temperature up or down.  Since the heater won’t change the entire tank’s temperature quickly, adjust the heater thermostat slightly and check back an hour later. Keep adjusting a small amount at a time until the tank is at the proper temperature.

If it seems like the heater isn’t working at all, it could be broken.  With the heater on, test the temperature of the water right next to the heater.  If the water right next to the heater is the same temperature as the rest of the water in the tank, the heater isn’t heating.  Make sure the outlet that the heater is plugged into is working correctly by plugging a different appliance into it.  If it is, your heater might be broken or have a blown fuse.

Types of aquarium heaters

There are several types of aquarium heaters to choose from. They all have varied uses, so it’s important that you choose the right one for your fish tank.

1. Submersible Heaters

Since these heaters are placed right in the water, they are much more efficient as compared to immersible heaters. Just ensure that there is enough space left around the heater to give your fish enough room to move around freely. In addition, these heaters shouldn’t touch the gravel because the difference in heat conductivity can crack the glass.  Most of the heaters we reviewed are submersible heaters because they are durable, reliable, safe, and easy to install.

2. Immersible heater

Otherwise known as a hanging heater, this type of heater is usually hang over the tank with the glass tube that houses the heating element is immersed in water. Immersible heaters are quite common, and the best option for people who are still new to keeping fish.

The aquarium hood needs an opening to accommodate this. It’s important to ensure that the immersible heater is properly secured because otherwise, it can electrocute your fish and even start a fire. This heater is not ideal for use in marine or brackish fish tanks. This is because if the water finds its way into the tube, it can lead to corrosion.

3. In-sump heaters

They require more room and offer the same benefits as in-line heaters. They are also easier to maintain, and are put in the sump.

4. In-line heaters

These are external heaters that involve either a filter or a sump. They are placed in the line between the tank itself and the filter or sump. They are a great option for larger aquariums, and prevent contact between fish and the heater.

5. Substrate heaters

These aren’t very common, and usually consist of wires as the heating element. The wires are buried underneath the gravel, from where the heat travels to the water. They are ideal for plant fish tanks, where the gravel keeps the plant roots too cool.

How to buy an aquarium heater

Fish are cold blooded animals and as such, they cannot regulate their body temperature like other mammals. They require the right external temperatures for them to thrive whether in the open sea or in a fish tank. Fish have a natural ability to survive in open waters because the heat conditions remain fairly constant. However, because aquariums are man-made habitats, more effort is required to maintain the right temperatures to ensure the survival of fish. Aquarium heaters provide an easy, effective solution to regulating temperatures in a fish tank. The challenge with getting an aquarium heater comes when consumers realize the overwhelming choices available to them from different manufacturers. Buying the right heater becomes an overwhelming process and knowing what to consider can lessen the stress of purchasing an aquarium heater. There are many aspects that go into buying a heater including:

1. Size of the heater: Fish tank heaters come in various sizes and the choice of a particular size depends a lot on the amount of water inside the fish tank, size of the aquarium as well as the average temperature of the room. To calculate the ideal size of the heater, subtract the current room temperature from the required temperature. Also determine the size of the aquarium. With these two measurements, determining the ideal size of a heater should be easy. Generally, a 25-watt heater is great for a five gallon tank, 50-watt for a ten gallon tank and so on. Larger aquariums may require more than one heater and in such a case, the heaters should be placed on either side of the tank to ensure even distribution of heat.

2. Type of heater: There are various types of aquarium heaters as discussed above, each of which serves a different purpose. Be sure to learn more about each type to make the right choice.

3. Placement of the heater: Placement of the aquarium heater inside the tank is another important consideration that should be made. You can choose to place a heater on the end or in the middle of the tank. This choice can help you choose an appropriate sized heater. Placing the heater near the inflow/outflow location is probably the best decision as this will ensure that the water is heated evenly.

4. Cost: Of course, you have to consider the amount of money you are willing to spend on this purchase. Heaters come at a wide variety of prices, which depend on the manufacturer and features they come with. If you are looking to buy the cheapest aquarium heaters, you should be on the lookout for immersible heaters.

5. Ease of maintenance: Cleaning and maintaining fish tanks is a lot harder than what many people imagine. The same applies to heaters. As such, it’s always important for consumers to choose heaters that are easy to clean and maintain.

6. Additional features: Other than the above factors, there are things that should be kept in mind when purchasing a fish tank heater. These include the thermometer or temperature scale that helps keep the water temperatures within a certain range. The temperature control is highly important particularly if you are keeping fish that are sensitive to temperatures.


For anyone who owns a fish tank, investing in the right aquarium heater is imperative as this could make the difference between life and death for their fish. The important thing is that whatever you buy should be durable and reliable. Our guide covers the various types of heaters, top products in the market as well as a buying guide to make the purchase process less of a hassle.