Do Goldfish Need an Air Pump?

They’re everywhere.

No matter what store you go to, if they stock fish tanks air pumps will be within arms reach.

Most fish tank kits even come with them included.

So surely you need an air pump to keep your goldfish from suffocating, right?

Or do you?

Do Goldfish Need an Air Pump?

Most fish tanks will not require an air pump to keep their goldfish healthy.  As long as you have a power filter or canister filter that agitates the water enough, you don’t need to install an air pump as well.  There are some situations where they are necessary, however.

Here’s the deal:

The air bubbles your air pump produces don’t do that much to oxygenate the water.

Sure, they do add a little oxygen, but the main job of the air pump is to agitate the surface of the water so that more water can get oxygenated at the surface.

If your filter is already doing that, you don’t need to add a filter on top of that.

Now, you might be thinking if you have a filter, you have free reign to skip the air pump.  After all, it’s already doing the same thing, right?

Not so fast.  There are some situations where you can’t rely on your filter.

  • Most notably, if you have a tall and skinny aquarium instead of a short and wide aquarium, you’re going to get far less oxygenation at the surface of the water.  In this case, you might want to add an air pump just to make sure your water is being properly oxygenated.
  • If your aquarium lends itself to having stagnant spots that aren’t circulating well, you might also want to supplement with a strategically placed air stone.
  • If your aquarium is overstocked, low dissolved oxygen is just one more thing that can stress out the fish in your aquarium.  In this case, you may settle on an air pump as a way to prevent one more problem from occurring.
  • Beyond this, an air stone producing a column of air in your fish tank just looks good.  You might want to add it even if you don’t technically need it.  But it’s not just for looks.

After all, your filter might not be oxygenating the water as well as you think it is.

Is Your Fish Tank Filter Up to the Job?

As we discussed, an aquarium filter can oxygenate the water by agitating the surface of the water.

The more the surface of the water is disturbed and broken up, the more oxygen is able to dissolve into your aquarium.

That means that if your pump isn’t agitating the surface of the water enough, your aquarium isn’t getting properly oxygenated.

There are a few main cases where this could happen:

  • You have an under powered pump.  If your pump is too weak, and the surface of your aquarium is only barely moving, you could be in trouble.
  • This can also happen if you have a canister pump that is improperly installed.
  • More importantly, if you have an internal filter, you should also invest in an air pump.  These are generally weaker and won’t oxygenate your water as much as an air pump could.

In these cases, you’ll need to supplement the filter with an air pump.

Don’t Leave It Up to Chance

At this point, you might be getting overwhelmed.

After all, this oxygenation talk may sound like a whole lot of voodoo.  You can’t see it, and by the time you know it’s a problem, it may be too late.

Plus, a lot of the symptoms of low dissolved oxygen content are also symptoms of half a dozen other things that commonly go wrong with your aquarium.

There is a very simple way to test for certain whether your fish have enough air to breath, however.

Enter: the dissolved oxygen test kit.

These can come in the form of test strips, a liquid test kit, or an easy to use electronic device that tells you your dissolved oxygen levels.

Which ever one you choose, they all do the same thing – tell you the amount of oxygen in the water.  (Usually in mg/l.)

You want to make sure your aquarium stays above 5mg/l of dissolved oxygen at all times.  Any lower than that will start putting stress on your goldfish.

Below 2mg/l, and your fish are likely to start dying.

Without a test kit, however, there’s no way to know for sure whether or not you’re providing at least that much oxygen.  And since the dissolved oxygen levels go down as water temperature goes up, you want to know if suddenly your goldfish don’t have enough air to breathe.

Don’t get me wrong – once you have your aquarium set up, you probably aren’t going to need to go out and re-test unless something significantly changes in your aquarium.  And with a small air pump being close to the same price as an O2 test kit, you may choose to spring for the pump instead.

But if you want to know for sure, that’s the way you can do it.

If you don’t want to test, you can also just observe your goldfish.  If you know what to look for, they will tell you if they’re having trouble breathing.

Are Your Goldfish Suffocating?

If you don’t have a test kit, all is not lost.

If your goldfish are suffocating, they’ll let you know.  All you have to do is look.

Here are some common symptoms:

  • Your fish may act lethargic, choosing to hang out on the bottom of the tank.
  • You might also see them at the top of the tank, gasping for air.
  • Your fish’s gills will be moving faster than normal, trying to pull in as much oxygen as they can.

At this point, it’s critical that you raise the amount of oxygen in your goldfish’s tank immediately.  Time is of the essence.

Emergency Oxygen

If your fish are showing signs of suffocating, you can add hydrogen peroxide in the amount of 2.5 tsp mixed into half a cup of water for every 10 gallons of aquarium water.

It’s important to note that this should only be used in emergencies (and only once), as it can damage your fish’s gills.  Find a way to increase oxygenation as quickly as possible.

Also check for ammonia, nitrates, and nitrites in the water as well, once you have the oxygen levels back up to normal.  (Many of the symptoms of low oxygen are shared by ammonia toxicity.  You don’t want to misdiagnose what’s wrong with your goldfish.)

A Greener Way to Oxygenate Your Aquarium’s Water

Another way to help oxygenate your goldfish’s water in the long run is to add plants to your aquarium.

Much like terrestrial plants do for the air, underwater plants oxygenate your fish tank’s water.

If you don’t have an air pump, this can be a beneficial part of your goldfish’s ecosystem.

Note: Goldfish are voracious foragers.

Put the wrong plants in, and they will devour them.

Therefore, it’s important to do some research before you waste your money on a new plant that your goldfish might immediately kill.

Here are a few ideas that work well with goldfish:

  • Anubius Barteri
  • Duckweed
  • Java Fern
  • Vallisneria

One Man’s Trash

Goldfish are messy.

They poop.  They eat your plants and leave bits to rot.  They just don’t take care of their aquarium.

This is a problem, because decomposing things release ammonia.  And the bacteria that break down the ammonia need oxygen.

Therefore, another tool in your arsenal should be to keep your tank as clean as possible.


If your filter is doing its job, you don’t really need an air pump for your goldfish.

The filter will do a fine job of oxygenating the water by itself.

That having been said, it doesn’t hurt to test your water.  (And, an air pump can make a very pretty addition to your tank.)

Have experience raising goldfish without an air pump?  Tell me about it in the comments below.