Air Pump

Should You Leave an Air Pump Filter For Fish Tank On All the Time?

6 min read

Ask any aquarist and they will say that the aquarium filter is the single most important component for your fish tank. In fact, the filter is a matter of life and death for your fish.

Since an aquarium is a closed system, organic waste can accumulate really fast, which could harm – or even kill – your pet fish.

That is why a filter is vital – to keep your aquarium clean and make sure no toxic compounds build up in it.

Aquarists commonly use air pump filter for fish tank, which is cheap and easy to set up. You may be wondering whether you should leave the air pump filter on all the time. Let’s answer that and also look at how long fish can live without air pump or filter.

Read on and find out. 

Air Pump

Why Use an Air Pump Filter for Fish Tank?

An air pump sponge filter is one of the cheapest and most convenient filters you can get – that is why they are so popular among hobbyists.

The sponge acts as a mechanical filter, trapping dirt and debris from your tank, and can be cleaned later.

Most importantly, the sponge houses the nitrifying bacteria that break down toxic ammonia and nitrites and convert them to nitrates, thus providing biological filtration.

As with any filter, water flow is important: the sponge filter achieves it through the air pump, which creates rising bubbles that generate a flow of water through the sponge.

An air pump works with sponge filters, undergravel filters, and fluidized bed filters; it cannot be used to create water flow for external filters such as hang-on filters, canister filters, and sump filters – these advanced filters use a power head for more efficient water flow.

Getting a filter with air pump is like getting two birds with one stone – you get a filter and also an air pump.

An air pump can improve the oxygenation of your tank and help with water circulation; some even get it for the aesthetic appeal of rising bubbles.

Should You Leave The Fish Tank Air Pump Filter On All the Time?

The short answer is yes, you should.

A filter is a vital piece of equipment for your aquarium; it is supposed to run all the time. Turning your filter off may lead to harm to your fish.

You may be asking, “What if I just turn off the air pump, the sponge will still act as a filter, right?” That’s where you are wrong: an air pump is needed to create a flow of water through the sponge, which is central to the functioning of a filter.

So without the air pump, the filter is effectively dead.

It’s even worse, as with no input of water you’ll starve the nitrifying bacteria of food and oxygen, leading to their demise. Building up a colony of these bacteria is hard and takes time, so you wouldn’t want to kill them and take your aquarium one step back.

An air pump filter also helps with oxygenation and water circulation, both crucial for the health of your aquarium. If your aquarium solely depends on an air pump for these, it is not a good idea to turn it off.

The only reason you would want to turn off the air pump is to save on the electricity bill or to get some respite from the noise it creates.

Yes, it is true that your electricity bill will rise if you keep it on all the time, but it probably won’t be such a big increase. You’ll have to remember that – as with most hobbies – an aquarium requires you to take some bucks out of your purse.

As for the noise, there are things you can do to make your air pump quieter without turning it off, such as getting an air stone.

If you are still insisting on turning off your air pump sponge filter, you can do so for a short period of time after carefully considering your tank parameters.

You must consider factors such as bioload(amount of living things), water quantity, frequency of water change, and filter strength.

If you think you have a small bioload for the amount of water you have, then your tank will not get dirty that fast and you can turn off your filter for a short period.

You may have to change the water more often to compensate for the reduction in filtering.

You can turn off your fish tank air pump filter more confidently if you have live aquarium plants, as they provide natural filtration as well as oxygen for your tank.

A word of caution: if you get into the habit of turning off your filter regularly, you may sometimes forget to turn it back on, which could lead to drastic consequences.

How Long Can Fish Live Without Air Pump Or Filter?

Filtration is an important process for any fish tank. Without proper filtration, excess organic waste can build up in your aquarium. Upon decomposition, this releases ammonia, which is toxic to your fish.

If your filter is running, the nitrifying bacteria in the filter will convert the ammonia to less toxic nitrates. Without the filter, ammonia can build up to dangerous levels.

Too much decomposition will also lead to smelly protein foam forming at the surface.

Moreover, a dirty tank is the perfect breeding ground for harmful bacteria and parasites.

Decomposition also consumes oxygen in your tank, leading to low oxygen levels. And since your filter also provides a source of water flow, water circulation in your tank will also be affected, leading to dead spots.

How long your fish can live without a filter depends on various factors such as the number and type of fish, water quantity, etc. It can be anywhere between a few days to a few weeks.

As for the air pump, as a standalone component, it is not always necessary for your aquarium as long as you have enough water to air surface agitation and adequate water circulation. That means your fish can live without an air pump.

How to Use Sponge Filter Without Air Pump

It is possible to use a sponge filter without an air pump. All you need is something to create a flow of water through the sponge to facilitate the filtration process.

That can be achieved through a powerhead; a powerhead is simply a water pump that is submerged under water.

Make sure you set up the pump to suck water through the sponge; do not pump water into the sponge as it will clog it from the inside and the flow will be limited.

Watch this video to learn how to do this.


An air pump filter for fish tank is a rudimentary filter that you can get for your aquarium. Since filtration is a vital process for your tank, you should leave the filter on all the time.

Only think of turning it off for a while if your water quantity is ample for the bioload you have and your tank doesn’t seem to be dirty; if your tank is too small, you have to leave it on all the time.

While your aquatic companions may live for a while without the filter on, it is best not to take any chances with their lives.

As long as you keep it on and clean it periodically, your filter will be working constantly to keep your tank clean and healthy – something you should be thankful for.

Thanks for reading.   


Stone & Spear Beer tallow soap

Written by:

Pet Aquariums

Have you any questions?