Aquarium Heater

If you are new to the world of fishkeeping, then the biggest mistake probably you can do, is to keep your fishes in the tank without adding an aquarium heater. It may be the case, that you have already started to notice the signs as the fishes will get sick easily and eventually start dying.

The aquarium heaters are available in different capacities with the ability to heat up to a certain volume of water.

Aquarium Heater Capacity Guide: 

  • 1200 – 900 Watts: Suitable for 300 – 800 Gallons Fish Tank.
  • 800 – 500 Watts: Suitable for 100 – 300 Gallons Fish Tank.
  • 450 – 250 Watts: Suitable for 45 – 200 Gallons Fish Tank.
  • 200 – 100 Watts: Suitable for 10 – 55 Gallons Fish Tank.
  • 75 – 25 Watts: Suitable for 25 – 5 Gallons Fish Tank.
  • 15 – 5 Watts: Suitable for 3 – 1 Gallons Fish Tank.

Why Should You Buy An Aquarium  Heater?

The reason you must have a heater for your fishes is that not all of the aquatic lives are capable of maintaining their body temperatures. So, if you are living in a cold weather where often the temperature runs in minus, your tank definitely needs a heater.

Other than that, reptile tanks are especially in need of a water heater, as they are cold-blooded animals and do not able to bear icy-cold. A water heater not only controls the temperature of the tank but also prevent the growth of some harmful bacteria from the waste produced by the fishes.

Types Of Fish Tank Heater:

Before buying a heater for your tank, you must know how does an aquarium heater work or which will be the best fit for you, as space is a great issue in the fish tanks.

There are 5 types of water heaters in total, available in the market. And each of them has their own benefits.

1. Hang On the Back Heater:

As the name suggests this heater can be hanged on the back or on the side of the fish tank to start operating. Often with the aquarium starter kits, this heater remains included, or you can buy it separately also.


  • It is probably the cheapest heater type available in the market, so no matter what your budget is, you can always go ahead and buy one for your tank.
  • As this is an external heater, you will not need any space inside your tank, so basically, this type of heaters is the best choice for small tanks.

2. Substrate Heater:

You need to bury this heater under the sand or under the substrate. There is a wire attached to this undergravel heater for the aquarium, which starts heating after switching the machine on and once the wire is hot enough, then the thermostat comes into play and regulates the entire water temperature.


  • These heaters are very easy to set up, and also are affordable in nature, hence perfect for the beginners.
  • As the heaters need to be kept under the substrate it will not block the view of the tank and will also acquire a minimum space.

3. Submersible Heater For Aquarium:

Sub-merged heaters need to be incorporated inside your fish tanks, where the controls must be kept above the waterline. These heaters are also often offered with the aquarium set up kits or you can buy them separately.


  • Absolutely inexpensive in nature, these heaters can be availed by the beginners effortlessly.
  • As these heaters are made of glass, plastic, aluminum or Titanium alloy, they are easy to camouflage in the tank, so that your view doesn’t get blocked.

4. In-filter Water Heater:

These are the two-in-one deals where you will both get a filter to eliminate the unwanted particles and also a heater to keep the temperature of the tank in control. After the filtration has been done by the tank, then the heater start heating the water and after that, the water is being released back into the tank.


  • If you are a novice and want both of the filter and the heater for your tank, then buying only one will be cost-effective and beneficial for you.
  • As the filter will take extra space in your tank, it is better to have both of the heater and the filter in one system.

5. InLine Heater For Aquarium:

This in-line water heater aquarium has pumps incorporated in them. After heating the water inside the machine, the heater pumps the warm water through the tubes in the tank.


  • These heaters are very useful for bigger tanks, where the water volume is higher.
  • These are very long-lasting and efficient water heaters to have.

How To Choose A Heater For Your Fish Tank?

Now, don’t get overwhelmed by the types of heaters available, all you need is to just understand your tank requirements and trust me you can easily get one of the top quality aquarium heater in the market if you are aware of all the know-how.

1. Determining Your Tank Space:

Obviously, before incorporating a water heater for the aquarium, you need to look for space, where you can set your heater up. If you have a small tank and you want to use the underwater environment for decoration and keeping fishes only, then you can easily go for the hang on back filters or the substrate filters.

But if you have a medium sized or larger tank then buying in-filter heaters, in-line heaters or submerged heaters will be appropriate.

2. Determining The Capacity Of The Heater:

500 W heater is undoubtedly a better option than a 400 W heater. Also, the more is the capacity, the more gallons of water can be heated efficiently by the heater. So, at first you must decide, the heater size aquarium, then go for the buying decision. But it is not that easy as there are several heaters available of the same watt in the market, so choosing becomes confusing.

Also, enquiring how long do aquarium heater last or that particular model does is crucial. To get insights on the best heater of a particular watt you can go ahead and check my review section where I have handpicked all the top heaters according to their capacity.

Bottom Line:

It is crucial to understand the need of a heater for your aquarium and act accordingly. If you want to give your fishes, especially the marine animals a healthy life, then adding an aquarium heater to your entire fish tank set up is essential.