Where To Place The Aquarium Heater? – Life-Changing Tips For A Healthy & Happy Aquarium

Last Updated on March 28, 2022 by Guillermina

Where to place the aquarium heater? This question usually bothers beginners (but sometimes experienced connoisseurs too), therefore stay with us and find out the answer.

With the exception of tropical species, most aquarium pets need warm water. In addition, it is very important to make sure that the water is always constantly warm to keep your fish’s immunity up.

Since we are still facing cold winter days, we need to pay attention to whether our aquarium heater is in good condition and working properly. Therefore, stay with us and find out where to place the aquarium heater as well as many other things crucial for a healthy and happy underworld.

What Is An Aquarium Heater?

Aquatic pets differ from mammals in that they don’t produce their own body heat. Therefore, they must rely on water temperature to maintain a healthy body temperature.

In all of this, the aquarium heater proves to be our best ally. It is a device used to warm the temperature of water in aquariums. It is a device used to heat the water temperature in aquariums, i.e. it ensures that the tank does not cool down too much and that the temperature remains stable during the day, even when the room cools off.

As for the types, choosing the right one is not difficult as long as you know the differences between the varieties of heaters.

There are 4 main heater types:

Aquarium Heater Size Vs. Tank Size

If you have a smaller aquarium and if your home is not very cold, the size of the aquarium heater should be 5 watts per gallon capacity of water. Accordingly, a 20-gallon tank should have a 100-watt heater.

On the other hand, if your tank is larger than 40 gallons, consider using two heaters. So, instead of one 200-watt heater, use a 100-watt heater that you will set up at opposite ends of the tank.

Where To Place The Aquarium Heater

The answer to the question “where to place aquarium heater” is quite simple, the best location is near the maximum water flow, such as the outlet (or inlet) from the filter, or in the stream of a powerhead. Such precise locating will allow fast and even distribution of heated water through the tank.

In addition, be sure to place it at a sufficient distance to avoid sucking newly heated water directly into the biofilter. Namely, if hot water is constantly coming in, it may overheat your beneficial bacteria. Accordingly, it is recommended to place the heater near the filter outflow. In this case, the warm water will be pushed along in the current circulation into the colder water.

If you are using a fully submerged heater, try to place it horizontally just above the gravel near the filter discharge. In addition, you can use an air stone to place under the filter intake. Its role is to pull denser cool water near the bottom of the aquarium upward, thus creating bubbles toward the flow of circulation and into the filter.

 Can aquarium heaters be fully submerged?

Ways Of Heat Distribution In The Aquarium Tank

Once you have found where to place an aquarium heater, you need to think about how to distribute the heat as well. There are three basic ways to do this, read more about each of them below.


Conduction means the typical spread of heat from hot areas to colder areas while seeking a state of thermal equilibrium. The heated water molecules gain kinetic energy and then begin to bounce spreading to all parts of the aquarium tank equally.

Furthermore, most of the heat transfer in the tank comes from the following two processes, i.e. convection and circulation.


Convection refers to the state in which the water from the aquarium becomes less dense and rises to the top as it warms, creating convection currents. The heater itself heats the water and it then rises to the top and displaces cooler water, which is denser so it sinks lower.


Circulation means the transfer of heat through the circulation of water by a filter pump. So, the filter mixes water to prevent the formation of any hot or cold zones.

In Conclusion

It is very important to take care of the temperature of your aquarium water because it is an important factor in the comfort and well-being of your fish. This is primarily because unlike humans and other mammals, fish don’t produce their own body heat.

That would be it! Now you know where to place the aquarium heater. If you have any questions, please let us know in the section below.

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Where A Heater Should Be Placed In A Fish Tank?

Regardless of the type (immersible heaters, submersible substrate, or filter), it is recommended to place the heater near the maximum water flow, to make sure that it quickly and evenly disperses heated water throughout the tank.

Can Aquarium Heaters Be Fully Submerged?

That's right, some types, or rather most of them are waterproof and accordingly fully submersible. What they have in common is that they all have a part of their construction, which must be covered with water to avoid damage.

How Do I Install A Heater In My Fish Tank?

Step 1

Choose the right feature heater for the number of gallons of water in your aquarium.

Step 2

Make sure that the aquarium heater is intact, that it doesn't show signs of damage, and more importantly, that there are no exposed wires.

Step 3

Choose a location and simply attach the submersible heater using the suction cups provided by the manufacturer.

Step 4

Take a thermometer and place it opposite the heater.

Step 5

Turn on your aquarium heater.

Step 6

Let it run for 24 hours and check the temperature every four to six hours.

Step 7

When it reaches a balanced temperature, it's time to finally add your aquatic pets.

How Do You Hide An Aquarium Heater?

If you want to hide your aquarium heater, you can use the most popular method, i.e. heater guards. They are designed to protect heaters from large fish but are also great for hiding equipment. They are made of dark-colored plastic, which can help you camouflage even some other parts of the aquarium equipment. You can also use regular aquarium decorations such as plants, stones, wood, etc.