Can You Turn Off A Fish Tank Pump At Night?

By Nadine Oraby | 2020 Update

I’ve designed my fish tank in a way that is very cost-friendly yet a well-established aquarium. This makes me satisfied that my fish are doing great and I’m also not spending an arm and a leg on the maintenance. Just one thing that bothers me is the air pump. Needless to say, it takes too much power. Keeping it on 24/7 isn’t a good idea for me when it comes to the electricity bill. Besides, it also makes a small noise and the tank is in my bedroom. Both these issues kept me awake for a few nights. Then I asked many experts and did my own research. What I found out should be known for all the people who own an aquarium. Because it’s not a simple yes or no.

So, here’s what I found out:

Turning off the air pump at night depends upon many factors. If your air pump works independent of filter, the aquarium is large, and inhabitants are less, then for sure, you can turn off the air pump at night. But if your air pump is integrated with the filter, the aquarium is small or/and the aquarium is too much populated then turning off the air pump wouldn’t be a good idea.

Let’s dive deeper to know why in some cases its harmful for the fish if you turn off the air pump at night, every day.

Why You Should Not Turn Off A Fish Tank Pump At Night? (Video)

What’s an air pump?

An air pump is an essential aquarium equipment that should be installed as soon as you buy the tank.

Why it’s essential? Because it increases the oxygenation in the water by increasing the surface area for gas exchange and also by producing agitation. When the air pump produces bubbles, the excess carbon dioxide goes out of the water, and oxygen from the air dissolves in the water.

The cons of the air pump are that it produces noise that can disturb you at night if the aquarium is right in your bedroom. Even if you buy the one that’s silent, even then the power that it takes makes it almost impossible for some to keep it on 24/7.

So, if you’re one of them and really want to know if you can, at least, turn off the aquarium pump at night, then read below.

Can you turn off a fish tank pump at night?

Well, it depends on the type of air pump you have and many other factors (yes, it isn’t that simple).

In some cases, it’s totally fine, while in others you really have to think twice as turning off the air pump might make your fish suffocated and they can die.

So, let’s look into the type of air pumps first.

The air pump that works independently

Some air pumps have their own cable, independent of the filter. In that case, it’s fine to turn off the air pump for 6 to 8 hours at night. But again, this is not the only factor that decides.

When the air pump that works independently of the filter is turned off, the oxygen level doesn’t drop significantly as the filter agitates the water enough that it regulates the gases well.

The filter cleanses the water by regulating it and this regulation also increases the gas exchange. So, this regulation is enough and it works for at least night time.

But this doesn’t mean that the air pump has no role then. The air pump is specifically designed to increase the oxygen level by one or the other way in the aquarium.

So, it’s important to keep the air pump on at least for the day time and then you can turn it off at night. This will save some money as well as you’ll have a sound sleep.

The air pump that is integrated with the filter

Now let’s talk about the aquarium pump that is connected to the same connection as of the filter. So, when you turn off the air pump, the filter also turns off.

Is it OK to turn off the air pump in that case? Absolutely not. You can’t afford to turn off the filter at night, every day. Filter cleanses the water from ammonia, nitrates, and other waste products. Filter enhances the natural decomposition cycle in the aquarium by regulating good bacteria in the tank so that they can absorb all the waste products easily.

So, if the filter is turned off for the whole night, it is quite possible that the waste will start accumulating in the tank. Also, good bacteria might die. This scenario is deadly for your fish, as fish can’t handle this much waste in their habitat.

So, it’s not about the oxygen regulation but about the accumulation of waste when the air pump integrated with the filter is turned off.

That’s why it’s not a good idea to turn off the air pump in this case.

Other factors that count if you want to turn off the air pump at night

You really have to consider your tank size and other factors before deciding whether you can turn off the air pump or not.

Before coming to the factors, it is important to mention that the air pump doesn’t provide oxygen itself. It just produces enough agitation in the water that the gas exchange becomes easier and as a result, the level of oxygen increases in the water.

So, all the factors should be considered that can hinder the gas exchange when the air pump is turned off.

The size of your tank

If the size of the aquarium is small then there are chances that your fish will suffocate if you turn off the air pump at night. A small tank means that there would be less surface area for gas exchange. Also, your fish might face serious problems if that small tank is overpopulated. Your fish might start gasping and become oxygen deficient. Fish would find it extremely difficult to breathe. So in this case, you should not turn off the air pump even if the filter is on.

On the contrary, if the fish tank is fairly large, then your fish will not get suffocated even if you turn off the pump at night. There would be enough room for gas exchange and carbon dioxide will not accumulate in the tank. Also, if your large tank has fewer inhabitants, then for sure it’s okay to turn off the pump at night.

So, if you have small to the medium tank, then do not turn off the air pump while the opposite is true for a large tank.

The number of fish in the tank

Not only the number but the size of the fish also matters. More fish and larger fish mean more gills that are absorbing oxygen. So, if you turn off the air pump, then there are chances that the oxygen level will dropdown.

But if the fish in your tank are small and they are less in number, then even if you turn off the air pump, the fish will easily breathe. But remember, don’t turn off the filter in this case as well.

So, if the fish are large and numerous, then don’t turn off the air pump at night while if the fish are small and fewer, then you can turn off the pump at night.

Plants in the tank

The plants in the aquarium provide oxygen in the day time by photosynthesis. But at night when there’s no light, plants respire. They use oxygen and release carbon dioxide.

If you have too many plants in the aquarium, then it’s good for the fish in the day time. But at night, the plants will also absorb oxygen from the water. In this case, it’s not wise to turn off the pump at night as your fish will find it difficult to breathe.

But if there are fewer plants, then they wouldn’t consume this much oxygen. So, you can turn off the pump at night, with the filter on.

So, if there are numerous plants in your tank then don’t turn off the pump while if there are fewer plants then you can turn off the air pump at night.

Nature of the filter

Some filters are submerged in the water, while some hang above, and produce a waterfall. While both serve the purpose, but they work differently.

The one that is submerged in water doesn’t produce much agitation, and thus less gas exchange occurs. While the one that produces a waterfall offers more gas exchange at the surface by moving the water.

If you turn off the air pump with the filter that is submerged, then there is a risk that the oxygen level will drop. While if you have the filter that hangs above, then you can easily turn off the air pump at night.

Note that not only the type of filter but other factors also count. You can turn off the air pump if you have a hang on filter, large aquarium, fewer fish and plants. But think twice if the filter is submerged, the tank is small but numerous inhabitants (fish and plants) in it.

Signs that indicate NOT to turn off the air pump

Even if you’re considering the above factors, you should also look for the signs which indicate that it’s not a good idea to turn off the air pump at night.

Below are the circumstances where you shouldn’t turn off the air pump. These cases appear when you turn the air pump off for a night and notice the unusual conditions.

If you find your fish coming to the surface of the water and gasping, then they are finding it difficult to breathe. Quickly turn on the air pump, and change 10 to 20% of water.

If your fish are swimming restlessly and opening their mouth rapidly, then the water doesn’t have enough oxygen. In that case, also, turn on the air pump and don’t turn it off again.

If the water becomes cloudy, then it means the water isn’t regulating enough. In that case, less oxygen can bind to the water. Don’t turn off the air pump as it will further make the water oxygen deficient. Change the filter and do a water change as soon as possible.

The Takeaway

An air pump is an essential equipment of the aquarium. But often you want to turn it off for night time. The reason may be too much power usage or too much noise. In both cases, you have observed certain things and if they are favorable, then you can turn off the air pump at night.

If your aquarium is big, has fewer fish and plants, has an efficient hang on filter, then you can surely turn the air pump off at night.

If you turn off the air pump and find your fish restless, then quickly turn on the air pump. It’s also good to perform a water change and never turn off the air pump again.

If you’re doubtful, then it’s advisable to buy a noise-free air pump and then you can keep it on all the time as it won’t disturb you at night.

Related Questions

Can you turn off the lights of the aquarium at night?

Yes, you should turn off the lights of the aquarium at night. This maintains the fish’s biological clock. In their natural habitat, they recognize the day when the sunlight penetrates the water. When the sun sets, they know it’s time to sleep and relax. So, it’s important to turn the lights off at night.

For how long can you turn off the filter of the aquarium?

It’s better not to turn off the filter ever (other than feeding time and aquarium cleaning). If in case you want to turn it off, then you have to make sure the ammonia and waste products don’t accumulate in the water. You can check it by using the test kit.

2 thoughts on “Can You Turn Off A Fish Tank Pump At Night?”

  1. Thanks for sharing this information, I was not aware of many things you have explained. Keep sharing this useful information with us.


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