Is an Air Pump Necessary for a Fish Tank?

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Oxygen levels in a fish tank are a big deal. Just like us, fish breathe oxygen, so it’s vital that the water in your tank contains enough oxygen. One popular way of oxygenating a fish tank is with an air pump. But are they effective and are the necessary?

Air pumps are not usually necessary for a fish tank. An air pump helps to oxygenate a fish tank by agitating the surface of the water. As long as you have an adequate filter for your tank, this should create enough of a disturbance making an air pump unnecessary. There are certain situations where an air pump is a good idea, but the primary reason for including an air pump in your tank is for aesthetics.

Air Pumps Aren’t Usually Necessary

As long as the rest of the setup of your fish tank is up to scratch, an air pump isn’t usually necessary. However, there are times when an air pump is a good idea, and there’s the aesthetics side of it too. Some people like the appearance of bubbles in their tank.

First, let’s look at what air pumps do and why they aren’t usually necessary. The primary purpose of an air pump is to help oxygenate water in your tank. Just like us, fish breathe in oxygen, so a well oxygenated tank is vital for your fishes survival. The main way water in a fish tank gets oxygen is through the surface. At the surface, carbon dioxide leaves the water and is exchanged for oxygen from the air. When the surface is disturbed, the water is able to take in even more oxygen.

With an air pump, it isn’t the bubbles themselves that oxygenate the water, but when they agitate the water at the surface. And they are effective at agitating the surface, so you might be wondering why they aren’t necessary. Well, as long as you have the right size filter for your tank, this will usually provide enough agitation to the surface to adequately oxygenate the water.

So air pumps do work, but usually, a filter will provide sufficient agitation to adequately oxygenate your tank. However, there are some circumstances when an air pump is a good idea.

When You Might Want an Air Pump

Most of the time, a filter will provide sufficient agitation to the surface of the water, but there are certain situations when this isn’t the case and you will benefit from the extra agitation from an air pump.

  • Warm water tanks – Warm water is not as effective at holding oxygen as cooler water and you are more likely to have low oxygen problems in tanks with particularly warm water (above 30°C).
  • Deep tanks – As I talked about earlier, oxygen enters the water at the surface. A deeper tank will have less surface area than a shallower tank of the same size, so the water will have a harder time taking in oxygen.
  • Heavily stocked tanks – Fish breathe oxygen from the water, so a heavily stocked tank will consume more oxygen and therefore need more surface agitation to oxygenate the water.
  • Heavily planted tanks – Although live plants will help to oxygenate the water during the day, they give off carbon dioxide at night. For a heavily planted tank, it’s a good idea to run an air pump, especially at night.
  • Aesthetics – If none of the above apply to you, you still might want an air pump simply because you like how they look.

Pros & Cons of Air Pumps

If you’re considering adding an air pump to your tank, there are some pros and cons you need to consider.


  • You might like the appearance – This one’s subjective, but as long as your filter is adequate, the main reason you should run an air pump is simply because you like the look of the bubbles in your tank.
  • They help with oxygenation – Obviously we’ve talked about this one already. If you tank meets any of the criteria in the previous section, an air pump is a good idea to help with oxygenation.
  • Fish (sometimes) like them – Some fish enjoy playing in the bubbles that an air pump creates. However, keep in mind that some fish don’t like them and they can stress them out.


  • They can stress your fish – Although some fish enjoy playing in bubbles, they can be stressful for certain fish. This can be particularly true for fish that prefer still water, like betta. However, even some betta have been seen to enjoy playing with bubbles, so it really depends on the individual fish.
  • You might not like the appearance – This comes down to personal preference, but whereas some people love the appearance of bubbles in their tank, some people prefer a still tank.
  • They are noisy – All air pumps will make a noise to some extent, but some are noisier than others. The COLLAR aPump (click to find on Amazon) is definitely one to check out. It has good reviews on Amazon, particularly for being quiet.
  • Running costs – Air pumps don’t consume a huge amount energy, but they do still add to the running costs of your fish tank.

Making Sure Your Tank Has Enough Oxygen

The first thing you want to do is make sure your filter is adequate for your fish tank. Filters will have a recommended tank size, and ideally, you want a filter that is rated for a larger tank than yours, but at least the same size. For example, a filter rated for 40L would be ideal for a 30L tank.

There are a couple of ways to know if your water is low on oxygen. One way is to purchase an oxygen test kit (click to find on Amazon). This would be a good idea for deep tanks, heavily planted tanks, heavily populated tanks, and warm water tanks – all of which are more prone to having low oxygen.

The other way is by monitoring the behaviour of your fish. If your fish are moving less and rapidly moving their gills, this is a sign that the oxygen levels are too low. If your fish are gasping at the surface, this can also be a sign that oxygen is too low, but keep in mind, they also do this when they are feeding. Fish with labyrinth organs like betta will also do this to make bubble nests. If your fish are gasping at the surface and they are not feeding or making a nest, you will want to test your water, do a water change, and increase the aeration in your tank.

Air Pumps to Check Out

Hopefully, you have now decided whether or not you want to add an air pump to your tank. If you decide that you do want an air pump, you can check out some popular options below. If finding a quiet air pump is a big deal for you, I would check out the the COLLAR aPump (click to find on Amazon) which seems to be the winner when it comes to noise.


To answer the question, no an air pump is not necessary for a fish tank. However, if your tank is likely to have a harder time with oxygenation (e.g. heavily planted or heavily stocked tanks), then an air pump can be a good idea to keep the surface of the water agitated. Other than that, you might want to include an air pump in your tank simply because you like the appearance. If you do decide to add an air pump to your tank, remember there are pros and cons to consider.

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