The 7 Best Heater for 20 Gallon Tank in 2023

A 20 gallon tank is one of the most popular sizes for aquarists, which is a standard size tank for small homes and offices. A 20 gallon tank can easily accommodate colonies of 20-30 small or medium-sized fishes or around 5-10 larger fishes. However, regardless of the number of fishes you keep in your 20 gallon tank, you will need the right heater.

Every fish has its requirements of temperature; for instance, cold water fishes can have different needs of climate than tropical fishes. In order to provide your fishes with a healthy living environment, you will need a good heater. If your water is not at optimal temperature, then your aquatic pets and fishes can stress out, loose colors, and even die. Hence, down below, I will be reviewing 7 best heater for 20 gallon tanks intending to provide you an easy guide to select the best heater model for your 20 gallon tank.


7 Best Heaters for 20 gallon tank

I have tested many different heaters for 20 gallon tanks before selecting these 7 heaters, which I believe to be the best heaters for 20 gallon tanks.


1. Orlushy Submersible Heater 100W

Weight and Dimension

 The Orlushy Submersible heater has a dimension of 10.8 x 3.7 x 2.2 inches with a weight of 13.62 Ounces.


 The Orlushy submersible heater is one of best heater for 20 gallon tank. It comes with a power of 100W, which is more than sufficient for 20 gallon tanks. This heater is made with shatter-resistant 2mm thick quartz glass, making it very durable and making it explosion-proof.

This heater also comes with suction cups for easy mounting inside the aquarium, and you can place it both horizontally and vertically. It also comes with a long 6-foot power cord, which helps to power it from any distance power source.

The temperature dial can be used to control the temperature easily in a range between 68-89 degrees Fahrenheit. The precision is very accurate, and due to the broad temperature range, you can use this heater for many different kinds of fishes.


  • It comes with a long 6-foot power cord.
  • This heater can be used in both saltwater and freshwater.
  • Includes suction cups for easy mounting
  • This filter has a digital thermometer.
  • The 2mm thick quartz glass ensures durability in the long term.


  • The weight is a bit on the higher sides.

Final Words 

If you are looking for a heater that can be used in both freshwater and saltwater and you do not worry about the weight, then the Orlushy submersible heater is the one to go for. It has a vast temperature range making it suitable for nearly all types of aquatic pets, and it also includes suction cups for easy mounting inside the tank.


2. Aqueon Pro Heater 150W  

Dimension and weight

The Aqueon Pro has a 4 x 17.5 x 2 inches dimension with a weight of 12 Ounces.


When it comes to the aquarium industry, Aqueon is a renowned brand; they have been making aquariums and its accessories for very long now. It is made of a solid, solidified plastic casing, which makes it totally shatterproof; so, this filter will serve you for very long.

The heating core is made up of aluminum, which doubles heating effectiveness while additionally expanding toughness. This heater has an adjustable temperature and can vary the temperature in a range of 6895 degrees Fahrenheit. Along with this, you will also get an indicator light, which is red when the temperature is heating and green when it is not heating.

The auto shutoff feature is also very unique and makes it more user friendly and easy to use even for beginners. The heater will auto shutoff when the heater overheats, and it resets automatically as the heater cools down.


  • It is made of hard plastic, which is more vital than glass.
  • The heater is fully submersible.
  • Shutsoff automatically as the heater overheats.
  • LED indicto9r to show when the heater is heating.
  • The aluminum core helps to provide more effective heating of the water.


  • The settings can be hard to read because of the black color.

Final Words

Aqueon Pro is a shatter proof heavily build heater that comes with an adjustable temperature range and provides with efficient heating of water due to its aluminum heating core. This heater is very easy to set up and easily accessible even by beginners because of the auto turn off and on feature. So if you looking for the best heater for your 20 gallon tank, you can go for this one without any hesitation.


3. Hydor Submersible Glass Aquarium Heater 100W 

Weight and dimension

The Hydor Submersible heater has a dimension of 3.5 x 2 x 12 inches with a weight of 8 Ounces.


Many good heaters break down or get seriously damaged when mistakenly taken out of the tank while running, but with the Hydor Subermsible heater, this will never happen because this heater is designed with exclusive PTC technology that helps the heater not get damaged or break down when run out of the tank. This is one of the best heater for 20 gallon tank.

The top heater comes with an extra thick rubber top, which will help prevent any types of shocks caused by light cuts in the heater. You will also find an easy-to-control temperature dial on the top of the heater. This dial will help you to control the temperature in a range of 6791 degrees Fahrenheit.

You will also find two suction cups along with this heater, and these suction cups will help you to mount the heater both horizontally and vertically inside the aquarium without any hassle.


  • It can be placed both vertically and horizontally.
  • Works in both saltwater and freshwater tanks.
  • Large temperature range
  • The scale is graduated for more precise control of temperature.
  • Compactly designed hence wont be taking much space inside the tank.


  • The heating element is not the strongest.

Final Words

If you are someone careless like me who forgets to turn off the heater while taking out of the aquarium, then the Hydor Submersible heater is the one for you. This is a compactly designed effective heater with a large temperature range. You can keep it either horizontally or vertically using the two suction cups that come with it for easy mounting inside the 20 gallon tank.


4. Boxtech submersible heater 100W

Weight and dimension

 The Boxtech heater has a dimension of 9.45 x 1.97 x 3.54 inches with a weight of 8.01 Ounces.


The Boxtech submersible heater is a powerful 100W heater; it works perfectly for any size of tanks between 10-30 gallons. Hence, it was a must to include this heater in our list of best heater for 20 gallon tank.

This heater is made from heat-resistant quartz glass that gives it high durability; just not it, the thermostat also has a shield in order to keep it water resistant. It also comes with a long 4.59 foot power cord for easy access to your power outlet.

The external controller makes it significantly easy to control the temperature, which can be controlled in a range of 68-90 degrees Fahrenheit. The heater also has a feature to auto turn off the heater when the set temperature is reached, and when the temperature goes down, it will again start to heat.


  • The external controller helps in easy control of temperature.
  • Suction cups for easy mounting
  • Can be used for tanks between 10-30 gallon.
  • This filter is compactly designed.
  • Auto shut off feature.


  • Some people may find the long wire to be troublesome.

Final Words

Boxtech submersible heater is one of the smallest yet effective heater for your 20 gallon tank. The heating core works effectively in providing perfect heating of your water inside the tank. The temperature range is large, making it useable for most types of fishes.


5. Hygger Saltwater Tank Titanium Tube Submersible Pinpoint Aquarium Heater – 100W

Weight and dimension

This heater comes with a dimension of 14.8 x 5.55 x 2.13 inches with a weight of 1.95 Pounds.


This is one of the lightest heaters in our list of best heater for 20 gallon tank. The Hygger heater is one of the best heaters out there if you are specifically looking for a heater for a betta tank. What makes this heater unique is the titanium tube, which is much stronger than glass heaters.

This heater is designed to be horizontally placed in the tank and stay completely submerged. It is advised that you keep the heater close to a strong water flow for the heater’s maximum performance. You additionally do not need to take the heater out always from the tank to change temperature since the temperature control can be done quickly using an external controller with a range of 32 104 degrees Fahrenheit. The temperature control has an accuracy of +/- 0..

It also has an auto shut off feature where the heater automatically turns off when you have reached your desired temperature.


  • It is made of titanium, which is more durable than glass.
  • Has a huge temperature control range with a precision of +/- 0.5 degrees.
  • It works very well with bettas and turtles.
  • An external controller can control the temperature.
  • Includes a digital thermostat.


  • It would be best if you try to keep it away from your fishes.

Final Words

The Hygger Titanium heater is a very powerful heater that is designed to durable as well as useful. Due to the fact that is made up of titanium, the heater is much stronger than traditional glass made heaters. Temperature controlling is straightforward due to the external controller, and the dual LCD display will show you the temperature in either Celsius or Fahrenheit.


6. UPETTOLS Submersible Aquarium heater 100W

Dimension and weight  

UPETTOLS submersible has a dimension of 13.2 x 2.4 x 2.2 inches with a weight of 11.22 Ounces.


This 100W submersible heater is designed to be covered with an aim that the fishes don’t come in direct contact with the heating core. The Outside is made from a quartz tube, which is very durable, and the heat transfer medium is designed with white corundum.

The temperature can be controlled with an external controller reducing your pain to take out the whole heater to control the temperature. The heater also supports auto off when you take it out of the water or even when the water temperature reaches above 36 degrees; it will also cut off power when the temperature exceeds your preset temperature.

You will also find suction cups that will allow you to mount the heater easily inside your 20 gallon tank, and the temperature can be controlled in a range of 60-90 degrees Fahrenheit.


  • It is designed with an external cover to protect your fishes from getting in direct contact with the heating element.
  • It is constructed with explosion-proof quartz.
  • This heater comes with indicator lights.
  • It has an auto shut-off feature.
  • Has suction cups for easy mounting.


  • UPETTOLS heater doesn’t have an automatic thermostat.

Final Words

UPETTOLS submersible heater is a well-designed heater that can perform brilliantly in your 20 gallon tank. This heater comes with external temperature control and also comes with indicator lights. The auto shut off feature when the temperature goes above 36 degrees Celsius or your preset temperature makes this heater very useful and easy to use.


7. Marineland Precision Heater 100W

Dimension and Weight

The Marineland Precision heater has a dimension of 3.94 x 1.63 x 11.69 inches with a weight of 9.6 Ounces.


You will be able to get precise control of your temperature with the Marineland Precision heater, and you can use this heater for both saltwater and freshwater tanks. It is very easy to change the temperature using the Marineland precision heater; with each click, the temperature will change by 1 degree. This click will initiate the mica core, which encircled by a mesh barrier. This barrier helps to circulate the heat evenly in the whole tank.

The temperature can be changed in a range from 65- 89 degrees. This filter comes with a thermal switch, which automatically turns off the heater as the water temperature goes above the set temperature and turns it on back again as the water cools down.

It attaches very firmly using the mounting brackets to the glass of the tank and will give you three window positions to observe the display that shows the temperature.


  • Mounting brackets are very strong.
  • Three window positions to read the temperature display.
  • The mica core makes sure to heat the water evenly.
  • Temperature can be changed in 1-degree increments.
  • The display is easy to read.


  • This heater can trap bubbles.

Final Words

The Marineland heater can be used for both saltwater and freshwater, and it offers a wide varying range of temperatures so that you can use this for almost any type of 20 gallon tank. The mounting bracket c comes with 3 suction cups, which ensures that your heater is strongly positioned inside the aquarium and allowing to view the temperature display clearly from different viewing angles.


Buying Guide for best heater for 20 gallon fish tank:

When you want to buy the best heater for a 20 gallon tank, there are many factors that you need to keep into consideration while making your decision.  You cannot just select a heater without knowing the key factors that play important in your selection of heater for a 20 gallon tank.

  • The wattage of the heater

You need to select the heater’s wattage very carefully since choosing a heater with lower wattage will mean that it cannot provide enough power to heat your 20 gallon tank, and selecting a filter with too high wattage will cause chances of overheat issues and damaging the heater.

As the wattage of the heater goes up, the power also goes up. Generally, for a medium sized aquarium like a 20 gallon tank, a heater with a wattage of 100-150W is more than capable of providing perfect heating.

  • Build Material

Customarily, aquarium heaters have created a heating core with glass tubes. Although these cores use glasses, they are very durable and strong. However, glass can still breakdown and cause serious problems inside your aquarium. So, while choosing your heater, please read the descriptions carefully about the build material; try to go for heaters that are made with quartz glass.

If you are still unsure about the glass, you can find heaters that have a heating core made out of strong materials like aluminum and titanium. You can check our list of the best heater for a 20 gallon tank for making your decision easier.

  • Range of temperature

The temperature range of the filter is another important factor since if you are not able to provide the perfect temperature in the water, your aquatic pets can die. So, be very careful while choosing the aquarium heater; check whether your picked aquarium radiator has a fixed temperature or you can select the temperature from a range.

Filters with variable temperature are a more suitable option since it gives you the flexibility to change the temperature according to your requirements.

Moreover, it is a superior choice, particularly if your fish require a marginally lower-or higher-than-normal temperature.

  • Heater type

Aquarium heaters come in many different shapes and sizes; most of the heaters for 20 gallon tanks are submersible heaters, which can be completely lowered in your tank; these heaters can have two different options of temperature controller, external or internal.

If you don’t like submersible heaters, you can choose from different options like undergravel or inline; however, according to my suggestion, submersible heaters are best for 20 gallon tanks. But, understand each type of filter carefully before choosing the one that will work best with your tank.

  • Safety features

The safety feature is a very important consideration when you are choosing any electric components; since you will be placing the heater inside your tank where your aquatic pets will be living, thinking about safety is a must. Please do not go for heater made out of regular glasses since they can easily crack, go for the one made from quartz glass; you can also select heaters made out of titanium.

While choosing the best heater, also look for auto shutoff and on feature when your required temperature is reached. This is crucial because it isn’t always feasible and easy to monitor the temperature by yourself, and with heavy fluctuation, in temperature, your fishes can stress out and even die. So, auto shut off and on feature will ease you out from this tension.



The following article was written to help you with choosing the best heater for 20 gallon tank. Heater plays a very important role in keeping your fishes healthy and keeping your water temperature optimal for perfect and happy living conditions of your fishes. Hence, choosing the perfect heater is very important. The market is full of different types of heater; some are good, whereas some are worst. So to make your decision easy, I have tested and created this list of the best heater for 20 gallon tank. You will find 7 of the best heaters available in the market for a 20 gallon tank in this list. Whether you pick them or not completely depends on you, but I can vow for them that they are the best performing heaters out there. I have also included a buying guide, which will help you further to choose the best heater for your 20 gallon tank. Do your own research before buying a heater, and I am pretty sure you will get back to my list of best seven heaters.

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