Everything You Need To Know About Setting Up, Installing & Regulating Your Aquarium Heater

I’m sure we can all agree that owning a fish tank comes with a fair bit of responsibility. The health and well-being of your fish need to be monitored daily.

As you know fish are cold-blooded and so using a fish tank heater is one of the more important aspects of caring for your fish.

Fish are described as cold-blooded, meaning that their body temperature varies with the external temperature. Fish do, however, produce metabolic heat (that is, heat derived from the oxidation, or “burning,” of food and from other processes), but much of this heat is lost to the outside at the gills. From lookd.com

The heater is a piece of essential aquarium equipment every fish keeper should have and using an aquarium heater is certainly something that requires a bit of understanding about the product itself.

Thankfully, this article will provide you with all the information you need to successfully install, set up and use a fish tank heater.


My Top 3 Favorite Heaters To Use

The Importance of a Fish Tank Heater

To understand how to use an aquarium heater properly it’s important to understand why a heater is needed in your aquarium.

The main reason heaters are needed is because fish are a rather delicate species. They need steady water temperatures to survive and avoid getting sick or even dying.

If their water becomes too cold they will have trouble eating, swimming, and may even die. These same health problems will occur if the water is too hot, except they won’t end up like fish sticks, but rather overheat and die.

Maintaining a steady aquarium temperature in your tank is especially important for tropical fish that require a constant temp of around 74 to 82 degrees Fahrenheit.

Stable warm temperatures are pretty much impossible to keep without heaters unless you live in a tropical environment.

The Four Types of Aquarium Heaters

Now that you have a better understanding as to why aquarium heaters are a necessary part of any aquarium setup, it’s important to understand the different fish tank heater types.

Having an understanding of the various types of fish tank heaters will allow you to choose the right one for your specific tank.

Typically, fish tank heaters come in four varieties:

  1. Immersible,
  2. Submersible
  3. Substrate
  4. Filter heaters

Let’s review each type.

Immersible Heaters

Consist of a glass tube where the heating coil is wound around a glass or ceramic insert. Some types of immersible heaters can be fully submerged in the water, but the main difference between immersible and submersible is that most hang along the side of the fish tank and have a marked water line that lets you know where the water shouldn’t touch the heater.

Submersible Heaters

Are one of the more popular designs as they can be fully submerged in the water. They usually come in the form of a long slender tube that can be suctioned to the sides of the fish tank.

To learn more about submersible heaters read: Can You Fully Submerge a Fish Tank Heater.

Substrate heaters

Are a flexible cable that contains a heat source. They are buried underneath the gravel on the bottom of the fish tank. substrate heaters are not particularly popular because they are mainly used for plant aquariums.


Filter heaters

Are built-in heaters that are used in conjunction with the filter of the tank. The water is heated as it goes through the filter.

For this article, we will mainly be focusing on immersible and submersible heaters as they are the most popular.

How Much Electricity (Watts) Does a Fish Tank Heater Use?

When purchasing an immersible or submersible heater it’s important to understand what wattage is needed for your specific tank.

The most common way to figure out how much wattage is needed to heat your tank is for every gallon of water your tank holds you’ll typically need 2.5 to 5 watts of power to heat it.

Depending on the size of your aquarium the heater size will vary.

For example,

A small 10 gallon Betta tank will generally need around 25–50 watts of power to heat it while a larger 70-gallon tank will require about 175–350 watts.

It’s also very important to get a solid idea of what the temperature is of the room your fish tank is residing in.

So, if the temperature of the room your fish tank is in is around 75 degrees, then you may only need a smaller heater to get it the correct temp your tropical fish require.

This requires a fair bit of monitoring and adjusting when first starting. Most fish tank owners will need to talk with an expert to get these specifications correct.

Your heater should also be able to fit easily in your tank so buy a heater that will fit.

For a more detailed look at this question check out How Many Watts Of Electricity Does A Fish Tank Heater Use where you’ll find an aquarium size chart along with the annual cost to run aquarium heaters of all sizes.

Watch: Selecting the Right Heater for Your Aquarium

How to Install an Aquarium Heater

Knowing exactly where to place your fish tank heater is another thing you must do correctly to keep your fish healthy.

Most suggest placing your fish tank heater where the water flows in and out of the filter.

Allowing the water to flow through the heater allows it to be evenly and quickly dispersed while heating up the tank faster and keeping the temperature controlled and constant.

For larger tanks, you may want to consider having two separate heaters on opposite sides of the aquarium. Typically, if your tank is 40 gallons or more, you’ll probably need two heaters.

Locate the ideal place in your aquarium depending on the size of the aquarium and how many watts the heater is.

Once you have the perfect location selected simply place the heater in the aquarium and use the suction cups provided to stick it to the glass.

In addition to the heater be sure to have a good thermometer so you can verify the temperature setting on a daily.

Place the thermometer on the opposite side of the aquarium heater to get a more accurate reading of the water temperature.

Further Reading: Can a Fish Tank Heater Catch on Fire

Setting Your Aquarium Heater

It’s of the utmost importance to understand the type of fish you have and what temperature they require. This will determine the correct temperature setting for your heater.

Once you set your desired temperature turn on the heater. Typical heaters will have a monitor light that indicates whether the heater is working if the light is on, so is the heater.

Watch: How To Install A Aquarium Heater Plus Regulate It

Recommended Best Aquarium Heaters You Can Buy

Below are some of the most reliable heaters you can find and for a reasonable price. Most of the heaters below are available in different sizes and are for use with freshwater aquariums.

When looking for a quality heater be sure to review the features of each heater and evaluate how easy it is to use, the maintenance requirements as well as any safety problems past users have reported.

Some advanced heaters come with temperature display settings and other cool add-ons.

1. Fluval M 200-Watt Submersible Heater

Fluval M 200-Watt Submersible Heater

Get The Fluval M 200-Watt Submersible Heater

2. EHEIM Jager Aquarium Thermostat Heater
EHEIM Jager Aquarium Thermostat Heater 100W

Get The EHEIM Jager Aquarium Thermostat Heater 100W

Aquarium Kits With Equipment Included

  1. Marina Aquarium Kit
  2. Aqueon Aquarium Kit
  3. Tetra Aquarium Kit

One last thing to keep in mind is that you’ll want to purchase a high-quality heater as the cheaper models tend to break easily. If this occurs the lives of your fish can be impacted.

Be sure to check up on your fish at least once and day to ensure that the heater is working properly and maintaining a healthy temperature for your fish.

Owning a fish tank requires some thoughtfulness and responsibility, but it’s well worth the trouble as you will undoubtedly enjoy a sense of calm and wonder watching your lovely fish swimming around.

Jack Dempsey
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