Aquarium Heater Options

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Aquarium Heater Options


Ideally, your discus aquarium temperature should be 84 to 86 degrees Fahrenheit. Use a heater to maintain this temperature. In this article, we’ll first explore the options you have when purchasing a heater. Afterward, we will describe heater placement.


When you purchase a heater, you’ll need to make sure that you find a heater that fits well in your tank. Find one that is specified for tanks that are the size of yours.

The quantity of heaters that you’ll need is determined by the size of your heaters. Many people use two small heaters instead of one large one. Then if one heater stops working, another heater is still heating the tank.


Heaters range from budget models to more expensive models. The types of heaters available include hang-on heaters, submersible heaters, substrate heaters, and filter heaters.

Hang-on aquarium heater

Hang-On Heater

Hang-on aquarium heaters are the cheapest and most popular option. However, they stick out on the back of the tank. For this reason, people who want their aquariums to look as beautiful as possible don’t use hang-on heaters. On the other hand, most discus keepers use hang-on heaters anyway. 

Submersible aquarium heater

Submersible Heater

Submersible aquarium heaters provide a middle ground between the cheapest model and the more costly heaters. Since submersible aquarium heaters go inside your tank, they won’t be hanging off the tank’s edge. Thus, they have more of an aesthetic appeal than hang-on heaters.

Substrate aquarium heater

Substrate Heater

Substrate Heater

Substrate aquarium heaters heat your tank evenly. Since the heating cables are laid below your gravel and substrate, these heaters are hardly visible in tanks. These heaters area also an excellent heat source for plants. The only problem with this type of heater is that if it falls, you need to dig below your tank’s gravel and substrate to replace the cable. These heaters are more expensive than hang-on and submersible heaters. 

Filter aquarium heater

Filter Heater

Filter aquarium heaters are some of the most expensive heaters available. However, they are beneficial because they heat water while it passes through your filter. Therefore, it won’t even look like a filter is in your tank.


Place your heater horizontally along the back wall of your tank near the bottom. Never place it in a vertical direction. 

Additionally, make sure your female discus don’t think that the heater is a suitable spawning surface. If a discus spawns on a heater, that discus could get burned. Then scar tissue would form and prevent the discus from laying eggs. Then there are two possible outcomes. In the first outcome, the eggs get reabsorbed back into the fish’s body, and the fish is not harmed. However, this outcome is unlikely. Very rarely do the eggs get reabsorbed back into the fish’s body. The second possible outcome is more likely: The eggs could get stuck in the fish’s body and decay, leading to a fatal infection. So be careful with your heater placement, and make sure that your fish don’t use it as a spawning surface.


  • What types of heaters are available?
  • Which heater types are more conspicuous than others?
  • Why is heater placement important?
  • Why is a heater important for your discus aquarium?
  • What varieties of heaters are best for your discus aquarium?

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