Aquarium Heating: Submersible Vs. Hang-on Heaters

Kate Barrington
by Kate Barrington
Unless you’re cultivating an aquarium that houses only goldfish, you’re probably going to need a tank heater. But should you go with a submersible or a hang-on heater?

Maintaining a stable water temperature in your tank is important for the health of your fish – sudden changes in tank temperature or constant fluctuations can cause your fish to become stressed and that can compromise their immune systems. Keep reading to learn more about the differences between two popular types of tank heater – submersible heaters and hang-on heaters.

The Pros and Cons of Hang-On Tank Heaters

You can probably guess from the name what a hang-on tank heater looks like – it’s simply a heater that hangs on the back of your tank. Most hang-on tank heaters fit into a plastic or metal casing that can be affixed to the back wall of the tank via suction cups. There may also be some kind of support that hangs over the back wall of the tank to keep the heater from sliding down into the tank. Hang-on heaters are easy to use and they come in a variety of different sizes to accommodate tanks of different volumes ranging from small 1 to 2 gallon tanks all the way up to 100 gallons or more.

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Some of the smaller hang-on heaters don’t offer an adjustable thermostat – they simply heat the water to a certain range of temperatures, generally in the 76°F to 82°F range. Other hang-on heaters have an adjustable thermostat so you can set the temperature as you like.

One of the potential downsides for this type of heater is that, depending on the placement, it may not heat all of the water in your tank evenly. This is most often the case when the heater is positioned on one side of a large aquarium. If you have a larger tank and choose to use a hang-on heater, you may want to get two of them.

What Makes a Submersible Tank Heater Different?

What makes a submersible aquarium heater different from a hang-on heater is the design. Submersible heaters are, as the name suggests, designed to be submersed directly in the tank. These heaters usually come with suction cups so they can be affixed to the glass near the substrate in your tank.

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Submersible heaters can be positioned either vertically or horizontally, according to your preference. For larger tanks, however, the horizontal position usually offers more even heat distribution. Submersible tank heaters, in general, also offers better heat distribution than hang-on heaters for larger aquariums. Again, however, the size of the tank and the position of the heater will be a determining factor.

When choosing a heater for your aquarium, there are a number of factors you need to consider to make your choice. For one thing, you’ll want to think about the size of your tank as well as the type of tank you have. After answering these questions, refer to the pros and cons for submersible versus hang-on heaters provided above to make the smartest choice for your tank.

Kate Barrington
Kate Barrington

Kate Barrington is the loving owner of two cats (Bagel and Munchkin) and a noisy herd of guinea pigs. Having grown up with golden retrievers, Kate has a great deal of experience with dogs but labels herself a lover of all pets. Having received a Bachelor's degree in English, Kate has combined her love for pets and her passion for writing to create her own freelance writing business, specializing in the pet niche.

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