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5 Best Aquarium Heater And Buyer’s Guide For 2022

best aquarium heater
Fish is a cold-blooded creature. It means their body temperature is largely regulated by the surrounding environment as they cannot produce their body heat, unlike humans. Therefore, they must rely on the temperature of the aquarium to maintain the required body heat.

In winters, at night, when the temperature falls below a certain point, it can cause severe stress to the fish. Expect it’s cold-water species you have in your home, the majority of tropical fish require a balmy and steady temperature limit. It is essential for their wellbeing. So if cold days are around the corner or have already begun, it’s time you get a heater for your aquatic pets.

Now, finding a reliable aquarium heater can be quite a task for the new fishkeepers. With a plethora of brands and manufacturers available in the market, it is likely to get overwhelmed. But for you, we have made the process of choosing the right aquarium heater easy-peasy. The following article is a detailed buyer’s guide that has touched on every aspect of choosing the best heater for a fish tank.

How to Choose an Aquarium Heater?

To find the best heater that adequately fulfills the needs of your fish tank, you will have to consider the points mentioned below.

Type of Aquarium Heater: To get started, the first thing you have to decide is the type of heater you want. Majorly, there are 3 types of aquarium heaters – hang-on-tank, submersible, and heating cable. To know which one is the most efficient or suitable for your aquarium, read the next section, where we have talked about each type in detail.

Aquarium Heater Size: Heaters come in different sizes. To determine the right size for your aquarium, you have to consider the volume of water in the tank, the average room temperature it is placed in, and the required temperature for the aquarium.

As a general rule of thumb, 5 watts of heat per gallon of water is sufficient enough to stabilize the water temperature at 10 degrees above the room temperature. The wattage ratings of a heater indicate its heating capacity or power. You may require a higher wattage aquarium heater if your room temperature is significantly lower than what it is your tank needs. If you aren’t sure what size (or watts) heater you should get for your aquarium, follow this simple formula to calculate it – subtract the required temperature for the aquarium from the average room temperature. The result obtained is the amount of heating you have to provide to the tank.

For example, if you have a 20-gallon fish tank placed at an average room temperature of 68 degrees F. And you have figured out that the best-suitable water temperature at which your fish thrives is 77 degrees F. Thus, for this case, the required heating will be 9 degrees F (77 – 68 = 9). As you apply the general rule of thumb stated above, a 100-watt aquarium heater is what you need for the tank.

NOTE: To have an effective heating mechanism, use an aquarium lid to help retain the warmth and prevent evaporative cooling. Keep in mind that depending on how much temperature you want to raise/ or heat your aquarium requires will dictate the size of the heater. Use the table above to simplify your decision. It doesn’t have to be complicated.

Budget: Aquarium heaters come in different price ranges. Buying a heater from a popular brand will cost you slightly higher, but it is going to be reliable in terms of customer service and performance, to say the least (not the case with every other popular brand in the market.) However, it doesn’t imply that you have to go out of your budget chasing products from well-known manufacturers. There are many aquarium heaters that are low-cost but work exceptionally well and are efficient in working. Always go for the heater that comes in your budget.

Personal preference: It is self-explanatory. When choosing a heater for your fish tank, probably the only thing that you don’t want to mess up with is the size of the heater. Rest everything depends on your personal preference and taste.

Types of Aquarium Heaters

Once you understand the difference between the types of aquarium heaters, it will be easy to pick one that suits your aquarium ecosystem the most. Keep in mind that it’s always your preference to decide on the variety you want to go for.

Hang-on/Immersible Aquarium Heaters: As the very name implies, hang-on heaters simply hang on the back of the aquarium. It usually mounts over the edge of the tank with the help of the suction cups or other fastening device attached to the heater. Hang-on heaters are partially submerged, and therefore, they tend to be less efficient than other aquarium heaters. However, it is a perfect fit for smaller tanks and beginner freshwater tanks.

The potential downside of this type of heater is that if it’s positioned on one side of a larger aquarium, it may not heat water evenly in the tank. So if you wish to use hang-on heaters on your slightly larger tank, make sure you have got 2 of them hanging on both sides. Also, keep in mind that hang-on heaters aren’t recommended on brackish or marine water setups because they can cause corrosion or electrical shorts if salt enters the heating tube by any means.

Submersible Aquarium Heaters: These heaters are designed to fully submerge in the tank water and sit near the substrate in your tank. It comes with suction cups that allow you to affix the heater on the rear of the aquarium. You can position a submersible heater both vertically and horizontally, depending on your preference. However, for better heat distribution, it is suggested to place the heater horizontally in the tank.

You can also choose to mount the heater next to the filter’s inlet as it will heat the water as soon as it comes back to the tank from the tube. Submersible aquarium heaters are more efficient and provide consistent heating compared to hang-on heaters.

Heating Cable: Commonly known as substrate heaters, these are primarily used as an add-on/or secondary heater for fish tanks. It looks similar to its name heating cable, as it comes in the form of wires which are placed under the aquarium gravel or substrate.

There was a time, mainly in the 90s, when these heaters were popular for their use in the freshwater planted aquariums. Well, currently, it’s the least used aquarium heater mainly due to its placement. Nobody likes to mess up with their substrate by digging up the wire in case they find the heater malfunctioning and want to fix it.

NOTE: If you can’t decide on the type of heater you want for your aquarium, take our advice only if you wish to, and go for submersible heaters. You won’t regret the decision.

Best Aquarium Heaters 2022 – Our Top Picks

By now, you must be cleared of the basics of aquarium heaters. And now it’s time to review some of the top-performing and reliable heaters we have found during our research.

Best for Smaller Tanks: FREESEA Submersible Aquarium Heater

Type: Submersible

Available Sizes: 50W, 75W, 100W

Reviewed Unit: 75W

Tank Size: 5-15 gallons (75W)

The oval-shaped FREESEA aquarium heater comes with an ultra-compact design making it an excellent choice for small aquariums. If you are someone who deeply cares about the aesthetic appeal of their fish tank, you just can’t say no to this visually impressive submersible heater.

The USP of this product is the large LED display that shows the real-time temperature. And the best part is you don’t have to buy a separate thermometer for that. FREESEA submersible has an effective heating mechanism. However, it may take up to 30 minutes to reach the required temperature, so have patience when dealing with this heater.

It has an automatic temperature control feature that allows the heater to stop by itself when it has reached the set up temperature. And likewise, when the aquarium temperature is lower than required, the heater will start automatically; no manual action is required. This heater comes with an external thermostat that enables you to set the temperature without getting your hands wet.


  • Large LED Display
  • Ultra-compact design
  • It’s made up of durable plastic
  • External thermostat


  • A gap near the suction cup area could be dangerous for small fish as they might get stuck in it.

Best for Larger Tanks: Orlushy Submersible Aquarium Heater

Type: Submersible

Available Sizes: 30W, 50W, 100W, 150W, 200W, 300W, 500W

Reviewed Unit: 500W

Tank Size: 50-80 gallons (500W)

Suitable for both marine and freshwater, Orlushy is one of the most widely used submersible aquarium heaters. It’s a budget heater that is both reliable and offers efficient heating. What makes this heater stand apart from other aquarium heaters is its sleek design and sturdy build quality. It’s also the USP of the product.

The heater comes with a temperature control knob that lets you adjust the heat and maintain it as per your requirements. There is an extra digital thermometer that comes free with the unit, which tells you accurate readings. In the heater, you will find a small LED light that works as an indicator showing when the heater is on and functioning.

Since it’s a fully submersible heater, it’s required to be placed underwater. You can position the heater either vertically or horizontally using the suction cups. Last but not least, there is an automatic shut-off feature Orlushy aquarium heater comes with, which allows it to stop heating when the setup temperature is reached.


  • Sturdy build quality and sleek design
  • Free thermometer
  • Adjustable temperature control knob


  • Suction cups are a bit tricky to adjust
  • The heater is heavy and feels bulkier for small aquariums

Eheim Jager Aquarium Thermostat Heater

Type: fully submersible

Available Sizes: 25W, 50W, 75W, 125W, 150W, 200W, 250W, 300W

Reviewed Unit: 50W

Tank Size: 7-16 gallons (50W)

When we talk about manufacturers of high-quality aquarium supplies, Eheim is a relevant name that can’t be skipped from the list. Eheim Jager comes with a number of features suitable for both marine and freshwater. There is this convenience of operation with the Eheim Jager submersible aquarium heater, and we believe this is what exactly makes it a must-try for aquarists. If you are a fan of precision and accuracy in temperature readings, you are going to love this heater for that particular reason.

Eheim Jager has a TruTemp dial that allows users to recalibrate the heater and adjust it 8 degrees on either side (high or low.) Equipped with the ability to recalibrate the heater is what adds up to the Jager’s reputation of being one of the most accurate heaters. It’s a highly durable heater made up of shock-resistant and shatterproof glass and comes with a robust chord. Although the heater has a number of USPs, its Thermo safety control is what gets us the most. This feature tends to turn off the heater automatically as soon as the tank’s water dips below a certain level.


  • TruTemp Dial for recalibrating the heater for precise temperature
  • On/Off indicator light for at-a-glance monitoring
  • Thermo safety control
  • Durable build


  • The heater’s rod is quite long, and it may not fit vertically in the relatively smaller tank.
  • You might find the temperature dial setup a bit hard to turn on or adjust especially when the heater is mounted on the tank glass.

Hygger Fast Heating Titanium Aquarium Heater

Type: Submersible fish heater

Available Sizes: 500W, 800W

Reviewed Unit: 500W

Tank Size: 60-120 gallons (500W)

With a temperature accuracy of +/- 1°F, the Hygger aquarium heater is one of the best performing and reliable heaters you can get your hands on today. It can be used in both marine and freshwater tanks up to 60-180 gallons. The large, easy-to-read LED display shows the real-time water temperature so you can glance at it and know your little aquatic pets are fine and under no stress.

The heater comes with a run-dry protection mechanism that allows it to auto shut off when the heating rod isn’t submerged or in contact with the water. In such a situation, the controller will start flashing the error code ‘er.’ The USP of the Hygger aquarium heater lies in its build quality. It is made of premium titanium and double sealed by a black protective guard that prevents explosion and corrosion. And it also protects your aquarium inhabitants against getting burned.

On the other hand, the Thermo control unit ensures turning off the heater when the water reaches a certain point or starts overheating to save it from melting the plastic case. It has an external temperature control built-in button that makes setting up the temperature a breeze.


  • It is made from premium titanium and double sealed by a black protective guard.
  • External temperature control keeps your hands from getting wet.
  • Temp accuracy of +/- 1°F.
  • Bright LED display.
  • Run-dry protection.


  • On some occasions, you may find the controller displaying unnecessary error codes even when the rod is well-submerged.

Fluval E300 Advanced Electronic Heater

Type: Submersible

Available Sizes: 100W, 200W, 300W

Reviewed Unit: E300 (300W)

Tank Size: 100 gallons (300W)

If you are looking for a feature-rich aquarium heater, then look no further than

Fluval E300 electronic heater. Equipped with dual temperature sensors, heaters from the Fluval’s E series are fairly accurate with their real-time readings. It comes with a bright LCD display that shows the temperature in both Fahrenheit and Celsius.

The USP of this heater is the visual alerts comprised of color-coding. Anytime there is a potential risk or fluctuations in the set temperature, the display color will be changed instantly. If the LCD screen turns blue, that means the temperature is lower than what you have set to achieve, green shows up when the heater is at the set temperature and its best, and red means the temperature has gone higher than the required limit. All thanks to the sophisticated VueTech system.

Another feature we love about Fluval E300 is its plastic housing. It acts as an integrated fish guard to keep the fish and invertebrates from coming in direct contact with the heater’s core. Isn’t it a much-needed addition?


  • Precision temperature control of 0.5 degrees.
  • Equipped with VueTech technology.
  • Advanced LCD display offering visual alerts.
  • Plastic housing for keeping the fish safe from getting burnt.


  • It does not heat quickly.
  • Sudden drops in the temperature control.
  • The low-flow indicator shows up even when there is adequate flow.

Do You Need a Heater in Your Aquarium?

Well, it depends on the fish species if you are going to need a heater or not. For example, if it is the tropical fish you have in your tank, then the heater becomes a necessity as they generally require a balmy temperature range.

Different species of fish have different water temperature requirements they are most comfortable in. Some fish like Japanese Ricefish and white cloud mountain Minnows can tolerate slightly cold temperatures. Whereas, Discus, Ram Cichlids, and certain Apistogramma Cichlids prefer hotter temperatures around 85°F.

You must do some research on the type of fish you got in your aquarium, and that’s how you will know whether or not you need a heater for them.

How to Place an Aquarium Heater for Extended Utility?

After buying a heater, the first question that comes into mind is how to position it in the tank to get the best out of it.

To cut the chase, an aquarium heater should be placed where there is maximum water flow. An ideal place in the fish tank would be nearby filter output as it will help in the distribution of the heat throughout the aquarium with the moving water.

Considering it’s a fully submersible aquarium heater, you can either place it vertically or horizontally. However, we suggest you mount the heater at a 45-degree angle for maximum heat distribution and greater efficiency.

Frequently Asked Questions (FAQ)

Q. Do you leave a fish tank heater on all the time?

Almost all modern aquarium heaters come with an internal thermostat that turns off the heat automatically when the temperature reaches a certain level. So yes, you can leave your heater on 24/7 and not worry about it.

Q. Are aquarium heaters dangerous?

There is no binary answer to this. However, aquarium heaters are usually safe, or it would be apt to say they are strictly manufactured to be safe. If you take the proper precautions and follow the instructions carefully when installing the heater, it would be unlikely for you to come across any mishappenings.

Q. Do aquarium heaters use a lot of electricity?

You can determine the amount of electricity used by an aquarium heater by considering a few factors. It includes the wattage rating of the heater, the size of the aquarium, and on average, the number of hours the heater runs in a day. Depending on your requirements, the operational costs of an aquarium heater can be expensive.

Q. How can I keep my fish tank warm without a heater?

There can be many things you can do to keep your aquarium warm, but we can’t cover all of them here. Moreover, it’s a huge topic and cannot be answered in a few lines. To keep it short and simple, move your tank to a warmer place in your house and additionally cover it with a lid/ hood/ or canopy.


And this is pretty much all for this extensive guide on the best aquarium heaters. We hope you like it. Let us know if this article helped you clear your doubts on the topic/subject.