Things to Look for to Purchase Heaters for your Aquariums (Complete Guide, FAQs, Upd.)

It’s easy to agree with you when you say heaters for aquariums are a headache to choose and buy. 

Keeping this in mind, we’ve spent weeks speaking to experts and experimenting with heaters in order to bring you this comprehensive guide.

In today’s post, we’ll be helping you figure out what kind of fish tank heater you need.

Do I Need an Aquarium Heater? 

Things to Look for to Purchase Heaters for your Aquariums (Complete Guide Upd.)

Some cold water fish such as Goldfish don’t require the water temperature to be maintained. If you have fish like these, you might not need to invest in an aquarium heater. 

However, for most fish in most aquariums, a heater is needed to balance the temperature in the tank and to keep it consistent. 

Most commonly found tropical fish require a water temperature of somewhere between 23 to 28 degrees Celsius (73 to 80 degrees Fahrenheit). If you have these fish, you’ll want to invest in heater. It will help you maintain the ideal water temperature in your fish tank using a thermostat which is usually built-in. 

It’s very important to not skimp out on a heater if your fish are the kind that need the temperature to be maintained as changes in water conditions can lead to several problems, mainly stress in fish. If your fish are stressed for an extended period of time, this could even lead to death. 

Large bodies of water such as the sea do not change in temperature drastically. Heaters help you mimic this natural environment for your fish.

Aquarium Heater Types:

Many different types of heaters are available out there which have different mounting properties and serve different purposes. The main types of heaters are: 

Hanging/Immersible Heater

An immersible or hanging heater, as the name suggests, hangs on top of your fish tank and a heating element is half immersed into the tank water which heats it up. 

This type of heater is most commonly used in beginner tanks. It provides basic heating but is not very cost-efficient. 

We strongly recommend not using this heater if you have a salt-water tank.

In-line Heater

This type of heater is usually fitted between the fish tank filter so that it is able to heat the clean water as it’s making its way back into the aquarium. 

It is usually made of heat-resistant plastic and is much sturdier than other types of heaters. This makes it perfect for people who have larger fish who are aggressive in nature such as African Cichlids.

Submersible Heater

Submersible heaters sit completely underneath the water. Like In-line heaters, this type of heater is also placed near the inlet of the fish tank filter so it heats up the water as it’s flowing back into the aquarium.

These types of heaters are able to maintain your tank water at a more stable temperature than immersible heaters.

Substrate Heater

This type of heater comes in the form of wires that are laid at the base of your aquarium underneath your substrate. 

The heat in your gravel can promote strong root growth. 

This type of heaters are much less common now and can be quite expensive if you want to get yours hands on one.

1. Size of the Heater 

When we speak of the “size” of the heater here, we’re not talking about the actual physical size of the equipment. We are referring to the capacity at which it can operate. 

This is measured in watts and it determines how effective the heater can be relative to your aquarium’s size. 

You should know that the larger a body of water is, the slower it loses heat and the longer it takes to heat up from a colder temperature. 

As a golden rule, it is usually preferred that you have a heater that has an operating capacity of at least 3-5 Watts per Gallon of water volume.

2. Cost of the Heater

The cost of heaters can vary depending on their type and operating capacity. 

It’s very important that you don’t cheap out when it comes to heaters as they control a very important factor that contributes to your fish’s health. Be wary of cheap heaters that are made from sub-par quality materials as they have a high chance of malfunctioning. If this happens, it can cause your water to overheat or become cold, either of which could be very harmful or even fatal for your fish.  

If you have a larger, deeper tank, you might need a heater that operates at a high wattage. This can get expensive but we strongly suggest that you make the investment. If you get a cheaper heater of a lower capacity, it won’t be able to heat your tank effectively and your fish will suffer.

It’s very important to strike a balance between how much your heater costs and the quality of the materials it’s made from.

3. Aesthetic Look

Things to Look for to Purchase Heaters for your Aquariums (Complete Guide Upd.)

Some people don’t mind equipment being a prominent part of their aquarium. If you’re one of these people, you might want to spend some time looking for a heater that looks aesthetically pleasing. 

If you don’t want your heater to be too prominent, you might want to invest in one that is inconspicuous and can be hidden by aquatic plants in your aquarium or other decorations.

4. Temperature Adjustment Properties

Cheaper heaters don’t come with temperature adjustment features. They just have an on/off switch and you are left to balance the temperature of your water. This is time-consuming and inaccurate. 

We strongly recommend that you get a heater with a built-in thermostat that is able to maintain water temperature on its own. It will save your time and energy and your fish will be much happier in their stable environment.

5. Safety Features 

There are some safety features that are essential to have in a fish tank heater. We recommend that you ensure that the heater you get has these features. 

Firstly, it should have an automatic shut-off feature for when the water becomes too hot. Secondly, it should have an LED light or an indicator that shows when your heater is on and actively heating the water. Lastly, it should be made from heat-resistant material in order to avoid fires and overheating problems. 

It is preferable that you get a heater that is fully submersible as heaters that are placed outside the body of water tend to break down more quickly due to external conditions and there are also chances of leaks in your aquarium if you use an external heater. 


A fish tank heater can be an essential piece of equipment for taking care of your fish. It can be the main factor that determines whether your fish live a healthy life. 

This is why we are of the opinion that proper research should go into buying a heater for your aquarium and we hope that we have been able to provide you with some valuable information today. 

Let us know what type of heaters you’re using for your aquarium.

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