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Should A Fish Tank Filter Be On All The Time?

Sometimes I wish to turn off the fish tank filter for some reason. One day I researched about keeping the Fish tank filter on all the time and here is a detailed explanation.

Should A Fish Tank Filter Be On All The Time?

should a fish tank filter be on all the time
It is recommended to keep the fish tank filter on all the time. The fish tank filter makes the tank clean and keeps the tank water fresh. The bad bacteria would be removed from the tank while the filter is on. Turning off the filter for hours would lead to a bad oxygen flow in the water which is harmful to the fish.

Many aquarist are worried about the fish tank filter lifespan and motor sound. Keeping the filter always on might reduce the filter life. Well, a good brand of aquarium filter can last for anywhere between 4-5 years or even more.

When talking about filter noise, most aquarium filters come quiet models. If you still concerned about filter noise, I will discuss how to reduce aquarium filter noise later in this article.

Can You Turn Your Filter Off at Night?

Most people turn off their fish tank filter at night times thinking that the filter is on throughout the day and turning it off at night might not be an issue. But that’s not how things work. The fish tank is a closed space where the water is in still or dead condition.

Water in the river and water in the aquarium is completely different. Even though you take water from the river and pour it into a fish tank, the problem would be the same. The oxygen flow in the moving water is fresh and healthier than the water in the still water.

Turning off the water filter at night leads to a bad flow of oxygen in the water and the fish might have problems in breathing. It is not possible to replace the water every hour. Fish tank filters remove the dead and bad bacteria from the water and keep the water fresh.

It is not a good idea to turn off the fish tank filter at night. Moreover, turning off the filter for several hours is also a bad idea. A good filter circulates the water inside the fish tank to provide proper oxygen to the fish.

All types of filters including Power Filters, Canister Filters, Undergravel Filters, etc are not exempt from this. Every filter has to run all the time. Filters that are above the water level will break the water continuously. This water flow will create more oxygen cycles in the water. If you can bear the noise of water flow from the filter, this is the best technique.

When To Turn Off The Fish Tank Filter?

should a fish tank filter be on all the time
You can turn off the fish tank filter while giving food to the fish. While fish eat the food, it is recommended to turn off the fish tank water filter for some time. This will give a break to the motor from getting burned without rest.

Turning the fish tank filter off for one night won’t harm fish but if the schedule is every day, then you are putting the fish’s health at risk. As we need fresh air for healthy lungs, fish need fresh water to breathe oxygen.

An important thing you have to note down is, how frequently you are turning off the tank filter. Once you turn off the fish tank filter, remove the dead particles from the filter before turning it on. This will remove the mess in your tank.

Other parts like air pumps make more noise and lights require more power than the fish tank filters. Ideally, the fish tank filters need to be ON all the time.

How Much Power Does The Fish Tank Filter Require?

The main concern fish tank owners have is power consumption. Let’s do the math here to know the total power consumption a fish tank filter uses. Fish tank filters are the lowest power-consuming parts compared to the other equipment in fish tanks.

On Average, a fish tank filter consumes 3 to 5 watts per hour. The power consumption depends on the fish tank size, the bigger the tank size, the more watts it takes. A medium-sized fish tank light consumes more power than a fish tank filter.

Turning off the fish tank filter at night just to save energy is a terrible idea. If you want to save energy, you can turn off the tank lights. From the fish tank power consumption, the filter consumes only 15% (this counts for only around 150kWh/year).

Fish tank filters can be heavy sometimes. Choose the filters that fit with the fish tank size. Having heavy filters for a normal fish tank not only consumes more power, but also will affect the fish’s health (especially the smaller species)

How To Reduce The Fish Tank Filter Noise?

should a fish tank filter be on all the time
If you cannot turn off the fish tank filter to make it quieter, is there any way to reduce the noise?

Fish tank filters are different in size and shape. All the advanced tank filters are quieter these days. If you fail to find the source of the noise, you can change the filter to a modern one.

If the water level is too low from the fish tank filter, obviously the waterfall makes a noise. Increase the water surface level just below the filter to reduce the noise. Not all filters are fixed above the water surface level, some filters can be fitted inside the water. In that case, bubbles would make a noise that is very minimal.

Will My Fish Die If I Turn Off The Fish Tank Filter?

As long as you are concerned about fish and have an idea when to turn off the filters, your fish will not be affected. The filter cleans the bad bacteria from the water and if the water is clean and free from the bacteria, fish will be fine. Also, how long are you turning off the filter? Holding it off for too long frequently will definitely harm fish.


Fish tank filters and motors are the most important equipment in the fish tank to keep the water clean and fresh. Your filter needs to be on 24×7 to filter and keep an oxygenated air flow.

Keeping in mind to save electricity or reducing the filter noise and turning off the filter will slowly kill your fish. As we need fresh air and food to stay healthy, fish need natural fresh water and food. In exceptional case while feeding the fish, you can turn off the filter.

If you were turning off the fish tank filter regularly not knowing the damage it can cause, you can test the oxygen level in the water. You can purchase Dissolved Oxygen Test Kits online to test oxygen level in your aquarium. Better late than never, try to test the oxygen levels before you turn off the filter next time.

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