Maintain Tetra Fish Tank Temperature Without Heater | Power Outage

Fish Tank Temperature

Some months ago, one of my friends also had added up tetra fish in his tank as he is fond of tetra fish. He was a bit confused on how to warm the tetra tank without a heater as we have got some issue with power outage once in a while. As I’m an experienced aquarist, he consulted with me, I gave him my ideas and technique to warm or maintain fish tank temperature without using a heater during a power outage. So, I thought of sharing it with other aquarists having the same problem.

Introduction of Aquarium Heater

The work of an aquarium heater is just to provide the heat to the aquarium. An aquarium heater is all time needed equipment for all the fish keepers. It helps to maintain the required water temperature of the tank.

Every living being needs an appropriate temperature to sustain. Unlike mammals, fish are cold-blooded creatures. Their body temperature depends on the water temperature they live in. This is the only reason you need to add a heater to a fish tank. Besides, an aquarium heater is a piece of must-to-use equipment in winter. Aquarium temperature between the range of 75 to 78 degrees Fahrenheit is the best living conditions for your tetra fish. Some of the best aquarium heaters for your tetra fish are;

  • Hygger Titanium Tube Submersible Pinpoint Aquarium Heater
  • Cobalt Aquatics 31000 Neo-Therm Heater
  • Tetra HT Submersible Aquarium Heater
  • ISTA Inline External Heater Aquarium Heater

Today, through this article I’m going to give you all information related to using a heater. After reading this article, you will come to know the importance of a heater, how it works, and mainly how to keep the tank warm without a heater for tetra fish. I’m going to share what to do to maintain the temperature even in some exceptional cases like power cuts. Are you guys ready to get started? Probably, yes, so let’s get started.

Alternative Tricks and Solution of Aquarium Heater

Appropriate water temperature is very necessary to tetra fish. Often many people ask ‘Is there an alternative to an aquarium heater’? Fortunately, the answer is ‘Yes’ but it is better to use only for exceptional and emergency cases. There are many other ways to maintain proper water temperature other than an aquarium heater. However, the aquarium heater cannot be replaced in the long run. Some tricks to maintain water temperature in the absence of an aquarium heater or during a power outage is listed below;

  • Place a thick blanket or towel around the tank to create insulation in the tank.
  • Place the tank to a warmer place at your house to raise the temperature.
  • Fill a plastic bottle with boiling water and dip it into your tank until the temperature is maintained.

The main point is to maintain the proper water temperature in the tank. But you have to consider, both too much heat and cold can affect your tetra fish and might lead to death. Knowing the alternative methods to maintain heat without a heater is worthy so far. So let’s have a closer look at the following more effective alternative solutions to maintain proper temperature in the absence of heater;

Using Blanket or Heavy Towel

This method is more practicable and easy for many fish keepers as everybody has a blanket or heavy towel at home. The main thing is you can cover your tank to avoid cold air passing into the tank using it. For larger tanks, you surely need a larger blanket. A thin towel might not work so go for a thick towel. As long as the towel or blanket is big enough and can avoid cold air, there will be proper water temperature within an aquarium for a while.

Maintaining the Room Temperature

Yes, maintaining the room temperature of 75 to 78 Fahrenheit is somehow effective to maintain water temperature in the absence of an aquarium heater. And as a matter of fact, installing a room heater is economical than the aquarium heater. But the issue with this is that your fish will be comfortable but not you and your homies due to the temperature.

Using a Hot Water Bag

This method is not the best option however, you can use it in an emergency case. For this simply take a hot water bag and dip into the aquarium. It will heat the aquarium water within minutes.

If the water bag is not hot enough, you can pour hot water into the bag and place it for some time in the aquarium. This method can work but is a bit unconventional, so using it only in an emergency is more preferable.

Shifting Tank in a Warmer place

Shifting your aquarium to a warmer place in your house is a good idea to maintain heat. Placing the tank bit nearby of the sun is fine but you have to avoid direct sunlight. As lighting is also a good way to create heat, placing a tank near or under some light is fruitful.

But don’t place the tank for much time, otherwise, algae will grow and might pollute the water within the aquarium.

Using heating pad

Using a heating pad is also a good solution to heat your fish tank without a heater. Heating pads are much better and reliable than just using a towel or blanket. Your tank will get instant heated up from the heating pad.

As in the current growth of the online market, you can easily get a heating pad like Pure Enrichment PureRelief XXL (20″x24″) Electric Heating pad with no problem.

Can Aquarium Lights be Used to Warm Up the Tank in Absence of Heater?

Unfortunately, the answer is close to ‘No’. Yes, aquarium lights do produce some amount of heat but it’s not enough for the fish. The main point is you cannot fully depend on the aquarium lights for heat as it only produces a small portion of heat.

So, overall using aquarium lights to maintain heat in your aquarium is not a good idea.

Can you Heat a Fish Tank Without Power?

Yes, you surely can heat the fish tank without power. For using the heater, lighting needs power and without power, you can’t run it. So it’s a prompt thing for you to know about how to heat a tank without power.

We have already talked about this. Using heating pads and hot water bags is a more effective way to maintain the heat of the tank without power. However, you can also use candles for your tetra fish for the sake of it. surrounding the tetra fish tank with some candles will surely go to boost up the heat in the tank. But you have to be a bit aware and careful while doing this.

Do I Need an Aquarium Heater for my Tetra Fish?

Tetra fish are hardy fish, they can withstand a wide range of water parameters. But keeping them in extreme temperature is not a good idea, so, adding an aquarium heater is a must. You shouldn’t take any risk when things come to the health of fish. An aquarium heater ensures the proper required temperature for the fish keeping the fish safe.

How do Aquarium Heaters Work?

An aquarium heater simply converts electricity into heat and hence maintains the proper temperature of the water in the tank. Most aquarium heater today can automatically turn off heating water once the temperature of the water the level you set up and automatically turn back on once the temperature decreases by a certain level.

Does the Aquarium Heater Size Matter?

Yes, the aquarium heater size surely matters. The size of the aquarium heater is directly proportional to the size of your tank. Choosing the aquarium heater that can match up with the tank is just knowing out the aquarium heater wattage per gallon.


Tetra fish are the adorable pets that need proper care if you are intended to add them to your tank. Though tetra is not that sensitive to environmental parameters, change in water temperature can surely affect the health of the fish. That’s why you have to maintain the proper water temperature of your tank for the sake of tetra’s health.

And talking about some exceptional cases other than aquarium heaters like power cuts or absence of heaters, you need to do it manually. I have provided all the required tips and solutions that you can apply to maintain the temperature even in the absence of a heater or during a power outage.

Tetra Fish Care


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