Can A Fish Tank Heater Catch On Fire? A Safety Guide 

Can a Fish Tank Heater Catch on Fire_

As an electrical appliance that produces heat, a fish tank heater constantly runs the risk of catching or starting a fire, and that is something that worries aquarists everywhere. So, in order to put the matter to rest, let’s find out whether aquarium heaters can actually catch fire or not.

Can A Fish Tank Heater Catch On Fire? If proper precautions and measures are taken before installation, fish tank heaters are safe. Factors such as:
Take the size of your fish tank into account, the power you will need to get the temperature you want. Decide between In-line Heater (suitable for smaller Fish tanks) or Submersible Heater. Get also a backup heater, in case one break. Always choose a new Titanium heater, the best option followed by aluminum ones with the automatic switch also. Stay away from used electric equipment especially for your fish tank.

Fish tank heaters do catch fire. However, there are a lot of factors involved in the cause of such fires. For starters, whether the heater will catch fire or not depends on its quality, the way it is used, how well maintained it is, and so on. Hence, just a generic ‘yes’ is insufficient to answer our question, for which, we need to dive deeper.

As we look into the deeper reasoning as to whether or not aquarium heaters are likely to burst into flames at our slightest inconvenience, we will come across various other questions that need to be answered before we reach our final verdict. Given the depth behind some of the logic put forward in regards to our original question, you will be amazed once you realize the complexity of the matter.

How Hot Do Aquarium Heaters Get? 

For every gallon of water, the fish tank heater is to be provided with 4 to 5 watts of electric power. Or, for every liter of water, the same heater is to be provided with 1 to 1.25 watts of electric power. This value will differ depending on the temperature you want to reach. 

To help you get a basic idea as to how much heat is needed for certain quantities of water, take a look at the chart provided below. 

Aquarium Heater Size Guide
Tank Size Heat
5 Degrees C
9 Degrees F
10 Degrees C
18 Degrees F
15 Degrees C
27 Degrees F
 5 Gallon/ 20 Liter   25 watt   50 watt   75 watt
 10 Gallon/ 40 Liter   50 watt   75 watt   75 watt
 20 Gallon/ 75 Liter   50 watt   75 watt   150 watt
 25 Gallon/ 100 Liter   75 watt   100 watt   200 watt
 40 Gallon/ 150 Liter   100 watt   150 watt   300 watt
 50 Gallon/ 200 Liter   150 watt   200 watt   2 x 200 watt
 65 Gallon/ 250 Liter   200 watt   250 watt   2 x 250 watt
 75 Gallon/ 300 Liter   250 watt   300 watt   2 x 300 watt


Most heaters on the market will not be available to you with a temperature regulator, meaning that you cannot manually alter the temperature of the heater. As you cannot fiddle with the temperature, you will need to choose heaters based on how much power they consume (in Watts).

Based on market research, most aquarium heaters operate in temperatures between 71 – 86 °F ( 22-30 °C ) which is the ideal temperature range for both fresh and saltwater fish tank setup. Hence, aquarium heaters will not go beyond 86 – 89.6 ºF ( 30-32 °C ) in most cases.

However, you might see an anomaly in the temperature of the heater if it is faulty in any way or if the power being provided to it is too much.

Are Fish Tank Heaters Safe?

Yes, and no – fish tank heaters can be deemed safe or unsafe based on certain factors. 

Any tool or equipment that has anything to do with electricity or producing heat is never really safe, no matter how good or well-made they are. Being an electrical appliance that produces heat, aquarium heaters are no different from this case.

If you take proper precautions and measures before installation, fish tank heaters are perfectly safe. What you as an aquarist need to remember is that fish tanks are usually not built to withstand excessive heat. Aquariums, where there is an excess accumulation of gaseous release, are also likely to burst if the gas gets agitated by the heat from the tank’s heater. 

Hence, you can easily guess that the fish tank heater alone is not the problem. It is merely a dormant element in the mix of things which is harmless as long as other factors or elements do not trigger it. 

There is also the issue of quality. Just like any other electrical equipment, the better the quality of the product, the higher its price tag. In no way should you choose a heater just because it is cheap. 

Now we ask the question – how do you choose the right fish tank heater?


What To Look For When Buying A Fish Tank Heater? 

If you want to avoid fire hazards caused by your aquarium heater, it is very important that you start maintaining precautions from the very beginning. So we start with your purchase of the tank heater.

Choosing a fish tank heater is not that difficult of a process. However, it does require you to put a lot of thought into it if you are willing to purchase something that will last you a long time. What you want in an aquarium heater is control over the temperature you want, durability, and of course, safety.

Here are the things you should ensure while buying fish tank heaters

  • Start with Tank Size: Take the size of your fish tank into account. Determine the power you will need to get the temperature you want based on the size of your tank (a chart for this purpose has been provided in the previous section).
  • In-line Heater or Submersible Heater?: You will have to choose from two different types of aquarium heaters. There is the in-line one and the submersible heater. In-line heaters are good for small water tanks. The submersible heater will warm the water in different ways, depending on where you place it in the tank.

In-line vs. Submersible Fish Tank Heaters

  • Consider A Backup Heater Also: Consider having a backup heater of the same brand and model. In case one heater fails while it is heating your tank, there will be a major and sudden change in temperature of the tank water. This could cause your fish to die. Hence, you should always keep a backup heater just in case.
  • Titanium or Aluminium?: Most tank heaters are basically naked metal rods that heat up when you pass a certain amount of current through them. What you need to know is the type of metal that is being used to serve this purpose. The metal being used should be good enough to reach the temperatures you want. At the same time, you would want the metal to be safe for your fish. Titanium heaters are by far the best option you have followed by aluminum ones.
  • Heater with Automatic Switch: It is in your best interest to go for an automatic aquarium heater. Such heaters will automatically switch off once the desired temperature has been reached.
  • Always Shop For New Heater: Try to stay away from the used equipment, saving money, in this case, is not often worthed.

Fish Tank Heater - Never Buy

How To Tell If Your Fish Tank Heater Is Broken? 

In order to determine whether your aquarium heater is broken or not, you need to follow a few steps.

Step 1:

Turn on your aquarium heater and look for the light on it which signals whether the heater is on or off. If the light turns on, you can be sure that the heater is receiving power from the power outlet and is working properly.

But what if your heater doesn’t come with a light? Or, what if your fish tank heater is working properly and it is just the light that’s broken? 

In such scenarios, we’ll be checking the condition of our fish tank heater by following the next step.

Step 2:

Assuming that we have no way to check whether the aquarium heater is working properly or not by checking its light, we have to proceed with an indirect method to determine the same. The approach we will be taking involves comparing the temperature of the fish tank water.

One way to check the temperature is by using a thermometer. 

Take two readings of the water – one before you run the aquarium heater, and the other a few minutes after you’ve turned on the heater. Compare the two temperature readings. If you see that the difference between the two readings is zero or any other insignificant value, you can be sure that your fish tank heater is not working properly.

The other way to check the temperature is by using your hand.

Dip your hand in the fish tank and move it slowly towards the heater. If you feel the water getting warmer as your hand approaches the heater, you can rest assured that it is not broken. In case you don’t feel the warmth, you can go ahead and give the heater a slight touch knowing that it is not hot enough to cause a burn. 

Step 3:

For this step, we will be assuming that it is not the fish tank heater that is at fault and instead, look for other causes as to why the heater is not functioning properly.

First, try the aquarium heater with a different power outlet. It is recommended that you try at least two other outlets to check the heater. Always make sure, you operate close to outlets with dry hands.

Next, try the heater on a different tank or water container which is smaller than your fish tank. Perhaps the heat is delivered from the heater is insufficient to heat a large volume of water. Hence, it is good practice to try it out on a smaller tank.

Having followed all these steps, you can confirm whether your fish tank heater is broken or not. Consider buy a new one,  the fastest way is to check pricing on Amazon for new affordable heater in your price range – here

Submersible Heaters for Fish

12 Tips To Keep You And Fish Tank Safe From Fire

Now that we know that fish tanks or fish tank heaters are not immune to fire accidents, we need to work out ways that will help us prevent such fires and keep us and our fish tanks safe.

Here are a few tips on how you can keep yourself and your fish tank safe from fire.

TIP 1:

Buy aquarium heaters from authentic dealerships only. Do not buy second-hand heaters, whatever you do.

TIP 2:

Do not opt for cheaper fish tank heaters. Spend a few bucks on a better or branded one. The aquarium heaters that are a bit expensive are likely to provide you with better service and a longer lifeline compared to those that are inexpensive or are just downright cheap. 

TIP 3:

Choose the heaters based on the size of your fish tank and the quantity of water in them. Different dimensions and volume of fish tanks require different amounts of heat. In order to maintain proper flow and distribution of heat from the aquarium heater to the rest of the fish tank, choose the one that goes with the size of your tank.

TIP 4:

Check the heater’s wire for leaks. If you notice any tear in the covering or core of the wire or find that it is worn out, try to replace the cord. If you cannot replace the wire, it is in your best interest to change the entire heater. 

TIP 5:

Make sure the power outlet you are using is not faulty. It is always a good option to connect the tank heater directly to the outlet instead of using an extender or a multi-plug. It is wise to get a GFCI outlet specifically for water tank heaters. link

TIP 6:

In no way should the power socket come in contact with water from the tank. Likewise, there should not be any loose wire connected with the outlet anywhere near the fish tank. This could cause electrocution. 

TIP 7:

Check the aquarium heater once a week to make sure that it is working properly. In case you find fault, replace it immediately. 

TIP 8:

Avoid letting the water level in the tank drop below a certain level. If the bottom of the glass is exposed to the direct heat from the heater, there is a very high possibility that it might crack or even explode. 

TIP 9:

Read the heater’s instruction manual carefully. Take a close look at the precautions. 

TIP 10:

Keep the fish tank heater unplugged while cleaning the tank or changing its water. 

TIP 11:

Avoid repairing the heater by yourself. Take it to a mender’s place if you want to get it fixed or buy a new heater instead.

TIP 12:

Do not take out the heater and place it on any dry surface while it is powered on.


As you can tell from the length of this article and the depths it has covered, the question of whether fish tank heaters catch fire or not has a very comprehensive answer to it. 

Under normal circumstances and with all safety measures in place, you can rest assured that your heater will not catch fire. Make sure you are following all the safety procedures mentioned above as well as the instructions set by the heater’s manufacturers, and hopefully, you are good to go with your maintained temperature with heater in your fish tank.


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