Aquarium Heating Solutions for Tanks Large & Small

By: Pet City   On: 28 April 2020 

Your fish tank is a mini ecosystem and a small change in water temperature can harm your fish. Here is a list of the top heaters for aquariums and which ones are more suitable for your tank.

Naturally, bodies of water will change as the seasons come and go and the temperature of the water will rise and fall slowly.

Your aquarium is a miniature ecosystem which can thrive beautifully under good conditions. However, due to the substantially smaller size compared to natural bodies of water your tank is more vulnerable to changes. All year round it is vital to have a heater in your aquarium, but with winter fast approaching the fluctuations in the weather can cause spikes in your water temperature. It is these sudden changes which can be fatal for your fish.

A heater, when appropriate for your size of tank, will not just warm the water, it will keep it at a consistent temperature.



Choosing a Submersible Heater

Generally talking about submersible heaters, the amount of ‘wattage’ your heater generates is directly equivalent to how many litres it is suitable for. However, if you cannot get an exact match it’s best to get a larger heater. For example, a 100w heater is suitable for tanks up to 100L, but if your tank is 120L it is best to go up to the 150W heater.


If your setup is over 250L, it’s a good idea to have 2x smaller heaters, one at each end of the aquarium.


Heater placement and orientation is also important. Some people opt to place their heaters horizontally, however it is prone to breaking this way, so we recommend vertically. Always position your heater in the tank where freshly heated water isn’t going to get sucked into the filter right away. Also, If your setup is over 250L, it’s a good idea to have 2x smaller heaters, one at each end of the aquarium.

If you have a small tank (under 25L), you will need a nano heater. You can read more about these below.


The Different Brands

Obviously, the quality of the heat output and thermal control depends on the quality of the heater. There are many different brands, varying in price and structure that offer different benefits. 

We stock three popular brands;

  • Aqua One: are a great all-round glass heater and are good if you are on a budget
  • Aquamanta (now Aqua One): with shatter-resistant glass and comes with a robust guard
  • Eheim: a German line of heaters, provide more efficient heating, have precision temperature control and have greater thermal regulation


Aqua One Heaters

Aquamanta Heaters




Heating Solutions for Small Tanks

Available are also heat mats, which are great for very small aquariums like Betta (Siamese Fighting Fish) tanks. The Reptile One Heat Mats have a thermal control setting for safety and to ensure you do not overheat your tank. Nano Heaters available in two types; glass, or a plastic preset option. The preset heaters are great for maintaining your water at 25°C, perfect for a Siamese Fighting Fish. The Glass Nano Heaters have an adjustable dial so you can set a specific temperature, similar to the larger heates but in a much smaller size. Both of these Nano heaters are suitable for little tanks.


Nano Glass Heaters

Preset Plastic Heater

Heat Mat for Bettas



Monitoring Temperatures

Thermometers are an essential tool (especially during Autumn and Winter) to have so you can easily monitor your tank’s temperature. For large tanks, a digital or submersible glass thermometer is recommended, however for small tanks made from acrylic or thin glass you can use a ‘Strip’ Thermometer to save space.


Nano Glass Heaters

Preset Plastic Heater

Heat Mat for Bettas



Have a Question?

Email our Aquarium Team