Top 10 Best Aquarium Heater (Submersible) with Complete Buying Guide

Not every person in this world lives in an area where the temperature remains the same throughout the year. Only a fish owner’s problem arises to an extent that he needs to find the best aquarium heater for their pet fish.

Best Aquarium Heaters

A drop in temperature can seriously affect the health of your pet fish if not taken care of properly. That is why I need to install an aquarium heater. 

In case you don’t have any idea on how to select the best aquarium heater then we have a quick buying guide at the end of this article, please refer to that for further clearance.

We have also done the hard work of finding the best aquarium heater for you so that you don’t have to.

List of Top 10 Best Aquarium heaters for fish tanks:

  • Bnzaq Fish Tank Aquarium Heater

The first one on our list is the Bnzaq fish tank aquarium heater. It has an adjustable temperature feature and it is a completely submersible heater that is available from 25 W to 300 W power options.

It is made from premium shatterproof glass and BPA-free plastic. The aquarium heater comes with 3 free artificial aquarium plants which you can use as ornaments in your tank.

This heater automatically regulates and maintains the water temperature for your fish, imitating the natural habitat of the fish.

It is usable in both fresh and saltwater. The Bnzaq aquarium heater is equipped with an adjustable temperature meter which automatically shuts down when the temperature reaches the required levels and it also turns on automatically when the temperature drops down in the tank.

You can easily place the heater in the horizontal or the vertical direction inside the fish tank but it should be completely submerged, but it is advisable to place the pump near the filter or pump of flowing water.


  • Multiple wattage options are suitable for small to large tank sizes.
  • Come with 3 free artificial plants for your aquarium.
  • Adjustable temperature range.
  • Automatic power on and off when optimum temperature is reached.


  • Very sensitive when doing water changes so don’t forget to turn off the heater 30 minutes before if you don’t want to break in two.
  • Turning the temperature knob takes a bit used to.
  • No digital temperature meter.
  • Orlushy Submersible Aquarium Heater

Next on our list is the Orlushy submersible aquarium heater. This is one of the most famous aquarium heaters and it is available from 100W to 500W so you can select according to the size of your tank.

It has an easy-to-adjust temperature knob that can be turned easily at small intervals of time.

The heating rod is made of 2mm thickened quartz glass which is very easy to hide in the tank and can be used in both fresh and saltwater aquariums.

The aquarium heater has a precise temperature dial to control the temperature of the tank between 68 to 89 degrees Fahrenheit within a 1-degree difference from aquatic climate.

It has a reliable thermostat that maintains a uniform temperature and shuts off when optimum temperature is reached.

Apart from the temperature control knob, it has a crash pad, indicator lamp for temperature, crash pad, and fire retardant padding.


  • Available in multiple wattages for all tank sizes.
  • An explosion-proof design, that is made of 2 mm thickened quartz glass.
  • Precise temperature dial.
  • It comes with an automatic shut-off thermostat controller.
  • Can be used for marine water, freshwater, hydroponics, and reef tanks.
  • Comes with a digital thermometer which keeps on telling you the temperature of water all the time.


  • For smaller tanks, many users have reported a difference in temperature from what it is set and what it is.
  • Marineland Precision Heater for Saltwater or Freshwater Aquariums

The Marineland precision heater is available in a 50W to 400W setting for different size tanks. It comes with an adjustable temperature dial that allows you to set the temperature 1 degree with every click.

There is also a thermal switch that automatically turns off and on to keep the temperature at the optimum level.

It has an advanced heating element that contains a mica core surrounded by a mesh heating element for superior heat transfer with enhanced durability.

Also, it has an advanced mounting bracket that securely attaches to glass and provides 3 window positions to view the temperature display.

It has an easy-to-view sliding scale that tells the exact temperature setting. The top dial view shows the setting from an additional location. 


  • Thermal switch for turning it off and on automatically according to optimum temperature.
  • Adjustable temperature dial.
  • Advanced mounting bracket so you don’t have to worry about falling suction cups anymore.
  • Easy to view sliding scale that tells the exact temperature setting and top dial shows setting from an additional location.


  • The heater makes a noise when the indicator lights click on and off.
  • The looks of this heater are just average.
  • Not so accurate in keeping the temperature. You will find a difference of 2-3 degrees which is quite common.


  • FREESEA Aquarium Heater with Aquarium Submersible Thermometer

This is another great aquarium heater from Freesea which is starting from 25 Watts and goes to 300 Watts for larger tanks.

It manages the temperature of the water from 63 degrees Fahrenheit to 95 degrees Fahrenheit. The company deliberately provides each customer a free diving thermometer so that you can observe the water temperature of the fish tank at any time.

Thermal switch for turning off and on the temperature for keeping the temperature at an optimum level.


  • Thermal switch for keeping the temperature at an optimum level.
  • Free digital thermometer.
  • 12-month warranty with 24-hour professional after-sales service.
  • It also has an indicator light.
  • The dial comes in handy while setting up the temperature of the heater.


  • Doesn’t have an inbuilt thermometer.


  • Tetra HT Submersible Aquarium Heater With Electronic Thermostat

The Tetra HT submersible aquarium heater is available in three sizes for 2-10 gallons, 10-30 gallons, and 40-55 gallons. 

The heater comes with an indicator light to let you know when it is turned on. Once it has reached the desired temperature the light will turn green from red.

Tetra HT10 uses a built-in electronic thermostat to maintain the temperature of the water and the heater is fully submersible which can be installed vertically or horizontally. 


  • Thermostat control.
  • Indicator light.
  • Aluminum oxide crystals improve heat distribution and transfer.
  • Heat and shock resistance.
  • The price is very low.


  • Only one suction cup was provided to hold it in place.
  • No temperature control. The heater does it automatically.


  • FREESEA Aquarium Heater Fish Tank Submersible Heater with LED Temperature Display

Another great product from Freesea is available in 3 sizes for 1 to 20-gallon tank size. It is a good product for small aquariums and keeps the water between the range of 59 to 94 degrees F.

The thermal switch turns off and on the heater to keep an optimum temperature.

It has a touch button, cyclic adjust temperature which is easy to use which needs to submerge fully for use.


  • Different and cool-looking design.
  • Thermal switch to turn it on and off automatically.
  • Compact and best aquarium heater for small fish tanks.
  • External Digital button to control the temperature.
  • 12-month warranty and 24-hour professional after-sales service.


  • Not suitable for larger fish tanks


This aquarium heater from Vivosun starts from 50W and goes up to 500W so you have the freedom to choose from different variants for different tank sizes. 

This aquarium heater has an inbuilt IC chip that controls the heater making it better for your aquatic animals.

It is made with IP68 the highest waterproof level and a titanium tube material that features explosion-proof and anti-corrosion engineering. 

It also has an overheat and water shortage protection. 

The touch button temperature controller is placed externally so you can keep the optimum temperature without getting your hands wet.

It has to be completely submerged vertically or horizontally.


  • Waterproof.
  • Out of water protection.
  • LED display at the end of the rod which shows the temperature with indicator light.
  • The titanium tube material makes it explosion/corrosion-proof.
  • Suitable for both fresh and saltwater.
  • External touch button controller.


  • The company says that you can only use it for a year.
  • Eheim Jager Aquarium Thermostat Heater

Just like other heating rods for aquariums, this is also a basic aquarium heater from Eheim Jager.

It has a thermal safety control that protects against running and turns off automatically when the water level dips too low.

A TruTemp dial that recalibrates the heater for precise temperature regulation.

It is made of shock-resistant and shatter-proof glass for fresh or marine water. 

The aquarium heater is available in multiple power models ranging from 25 watts to 300 watts.


  • Trutemp Temperature dial for recalibration of heater for precise temperature regulation.
  • Thermal cut-off and on to manage the water level.
  • Made of shock-resistant and shatterproof glass.
  • Good for both fresh and saltwater.
  • Indicator light.


  • You will need a little getting used to understand the working of precision dials.


  • Penn-Plax Aquarium Heater

This aquarium heater from Penn-Plax comes in different power modes ranging from 25W to 300W for different sized tanks.

The heater sets and maintains the temperature within 1-degree accuracy and features both Fahrenheit and Celsius temperature with easy to read gauge.

This fully submersible heater needs to be placed vertically or horizontally inside an aquarium.


  • Maintains the temperature within a 1-degree range from the set temperature.
  • Both Fahrenheit and Celsius scale.
  • Has a preset temperature of 76 degrees Fahrenheit which is reprogrammable.
  • Very affordable.


  • The heater is quite delicate so you have to be careful while handling it.


  • hygger Submersible Digital Display Mini Aquarium Heater

This submersible aquarium heater is very cool to look at. It is good for small fish tanks only as it is available only in 2 power modes only 50W and 100W for 1-13 gallons of water.

The length of the power cord is a good 5ft long. It can be placed on the walls of the aquarium using 2 strong suction cups.

It has a built-in thermometer which shows the temperature of the water constantly.

It has a thermal setting to keep the temperature at an optimum level.

The heater also has an ABS heater guard to protect your fish.


  • A digital LED display that shows only Fahrenheit temperature
  • Memory function in case of power down.
  • Best suitable for small round and square aquariums especially for betta fishes.
  • Good for both fresh and saltwater.
  • Shuts off automatically when the top part is taken out of water.


  • The controller is not waterproof.
  • Only Fahrenheit temperature display.
  • Not suitable for large fish tanks.

Final Thoughts:

When you will first start using an aquarium heater you will notice that the temperature will not be the same which you have set. A slight variation is alright, all the aquarium heaters do that.

Based on price, usage, and performance we have selected Orlushly Submersible Aquarium heater as the best aquarium heater for home use as it is fulfilling all the purpose

Buying guide for Aquarium Heaters

Things you need to consider before buying a good aquarium heater for your pet fish:

  • Type of mount

There are mainly 3 types of aquarium heaters when it comes to a mount type:

  • Hang on to the aquarium heater.

Generally, the hang-on aquarium heaters mount onto the rear of the tank with the help of a suction cup or hooks. 

Hang on aquarium heaters are generally good for small fish tanks as they are partially submerged in the tank and tend to be less efficient than other kinds of heaters.

Using a hang-on aquarium heater for a large tank is probably not the best idea as you will require multiple heaters which will eventually increase your electricity bill.

  • Submersible aquarium heater

As the name suggests submersible aquarium heaters are completely submerged in the tank. They are also mounted on the back of the fish tank in horizontal as well as vertical directions

Submersible aquarium heaters are more efficient for use in larger tanks as they provide more heat due to full submersion.

  • Aquarium heating cable

It is a rod-type aquarium heater that is usually placed under the gravel or substrate and connected to a control unit.

This type of aquarium heating rod is best suitable for freshwater planted aquariums but with saltwater reef systems they are not the best choice as you have to dig up the substrate if the cable needs to repair or replace.

  • Selecting the right wattage for the aquarium according to the size.

This is the point that causes the most confusion for many. You have to select the wattage according to the capacity or volume of the tank. As a general rule of thumb, you have to use between 2.5 to 5 watts per gallon of the volume of the aquarium.

Now, this depends on the type of fish which you are petting as different fishes require different temperature water.

For better understanding please refer to the table below.

Aquarium Volume (In Gallon / Liter)Wattage required (5 degrees C & 9 degrees F)Wattage required (10 degrees C & 18 degrees F)Wattage required (15 degrees C & 27 degrees F)
5 Gal/ 20 L255075
10 Gal/ 40L507575
20 Gal/ 75 L5075150
25 Gal/ 100L75100200
40 Gal/ 150L100150300
50 Gal/200L1502002X200
65 Gal/ 250L2002502X250
75 Gal/ 300L2503002X300


For larger fish tanks you can use a combination of heaters at different ends for better heating practice.

  • Location

The location of the aquarium is also a major factor whether you have placed it near an air conditioner or a window. Is it placed in a sunny room or the basement?

  • Display meter

It is an LCD screen that provides information such as the temperature of the water and some aquarium heaters have different colored lights where generally blue color shows too cold, red shows too hot, and green means just right.

Some people get confused when they see  LF written on their display meters. It means that the heater is in a low flow area.

  • Heater guard

You don’t want your fish to die by wedging themselves and getting stuck behind the heater. That is why you need a plastic covering especially if you are using a submersible aquarium heater.

This is a plastic covering that is designed to protect your fish from getting in direct contact with the heater’s rod. It can be removed easily during the cleaning process.

  • Adjustable temperature

Generally, there are two types of temperature control knobs that are a dial and a simple switch. Adjusting the temperature changes the behavior of fishes.

Some fish diseases are treated automatically when the temperature is raised and a lower temperature induces breeding activities.

  • Dual temperature sensor

It gives you extra reliability so that you get accurate and real-time water temperature.

  • Warranty

This goes without saying as an aquarium heating rod is an electronic device at the end of the day. It is always suggested to go with a renowned brand with a warranty of at least 1 year if not many.

  • Maintenance and cleaning 

However, modern aquariums require very minimal cleaning but it is advisable to select an aquarium and an aquarium heater both of which require minimal cleaning.

  • Price

The price of an aquarium heater depends on a lot of factors such as size, wattage, type of heater, and many others. You may find some aquarium heaters priced at $20 which others at $100

Fishkeeping can be a costly hobby if you are planning to pet some exotic fishes that require special features such as a perfect water temperature otherwise they will die.

That is why you should select an aquarium heater accordingly. You should not worry too much about the money as the life of your pet fish to understand depends on it.