Fish Tank Heaters

Making sure the temperature of your aquarium is correct is a very important part of keeping fish. Unlike humans and most other animals, fish are unable to produce body heat, meaning that a fish tank heater is the only way of keeping them at the correct temperature.

Different fish types require different temperatures to live and thrive in because of the climates and parts of the world they are normally located. Getting the correct heater for the size of your tank and the type of fish you have is one of the main things to consider when building your aquarium.

Different heater types

There are five main types of heaters available for fish tanks. Which one you end up picking will be based on the type of fish tank you have and the type of fish you plan to keep.

Hanging / Immersible heaters

The most practical solution is a hanging or immersible heater. These heaters simply hang over the top of the aquarium and the element encases in a glass tube sites within the water and provides heat. These are perfect for freshwater tanks and are normally included with off the shelf kits.

One downside of a hanging heater is that they are not as efficient as others and not recommended for saltwater fish.

Submersible heaters

These heaters are coiled elements covered with glass or plastic tubing. In most cases you will find them supplied with plastic casing as they are less prone to cracking under heat than glass over time.

The submersible heater itself sits at the bottom of the water in the tank and ideally should be placed near the inlet of the filter so the water is heated as it comes back inside the tank.

Compared to a hanging heater a submersible is capable of keeping a more stable temperature throughout the fish tank.

Filter heaters

There are some filters you can buy with built in heating elements so as the water passes through the filtration system is also heated. A great option for those who want a less complex setup and can be neater looking. The downside of a combined filter and heater is that if one part breaks the whole unit may need replacing.

In-Line heaters

The perfect solution for tanks with larger fish where components can easily be damaged over time, these heaters are fitted between the filter or sump so that water can be heated on the way back inside the tank.

Substrate heaters

Less commonly found these days, a substrate heater is normally used in addition to other heaters. They are quite expensive to buy so not normally a recommendation compared to the alternatives available, unless you specifically have a reason to need one.

Heater size guide

Heaters come in a range of different sizes depending on the size of the tank and volume of the water inside, as well as the room temperature. The following will give you a rough idea of the type of heater size you may need based on the tank size:

5-10 gallons – 25-75 watts

20-25 gallons – 50-200 watts

40-50 gallons – 100-400 watts

65-75 gallons – 200-600 watts

For smaller or nano tanks and bowls, you can actually get mini heaters which are far smaller and compact than traditional tank heaters. These are quite a new concept but work perfectly to overcome the challenge of heating up very small aquariums!