When it comes to answering this question whether you need an air pump for a fish tank or not, it is necessary to first understand what an air pump really does when it gets installed. As the name itself suggests it pumps outside air into the fish tank water via a tube.
One end of the tube is submerged in the fish tank water and the other end is connected to the air pump outlet. The pump forces outside air into the fish tank water via the tube. This pump obviously runs on electricity and sits outside the fish tank.
The end of the tube which is submerged into the fish tank water usually has an air stone at the end which is a small cube shaped stone. This stone is porous so that air can easily escape into the surrounding water. Due to porous nature of the stone bubbles of air are formed that travel to the top of the water surface creating a beautiful visual display.
The forced air escapes from this air stone and travels to the upper level of the water and escapes it finally into the surrounding air. Many people have a misconception that oxygen from this air gets mixed in the water. But the truth is air bubbles travels to the surface of the fish tank water where it breaks or agitates the surface of the fish tank water.
Due to this agitation of water surface it’s surface area increases and exchange of gases takes place. Carbon dioxide from water gets released and fresh oxygen gets into the fish tank water. Fish need his dissolved fresh oxygen for breathing and survival.
Thus an air pump helps to increase area of water surface at the top of the fish tank by forcing air in the water that moves up.
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But do you really require an air pump?
The answer to this question is actually very simple. If you have enough oxygen in your fish tank then obviously you don’t need added equipment that runs on electricity to be added. When oxygen in the fish tank decreases, normally fish will gasp for air at the top of the water surface. But in a tank with sufficient oxygen flow an air pump is obviously not required.
Normally a fish tank with a filtration system will circulate water enabling easy oxygen exchange during intake of water in the tank. However many fish tank owners prefer to have an air pump just because of the awesome visual display that gets created in the fish tank. As mentioned earlier most air pump end with a porous air stone at the end that gets submerged in the water which is responsible for the bubble formation that gets released.
Many air pumps also have a control knob that controls the amount of air being forced in the fish tank water. This knob is present on the air tube but sits outside the fish tank water. This is just a small circular type knob that can be rotated to control the air flow.
Another situation when you will not require an air pump is when you have other means to agitate the water surface in a fish tank. Other means may include a powerhead. This is installed inside the fish tank water near the top surface of the water and pointed upwards.
This agitates the water surface increasing it’s surface area making it easier for exchange of carbon dioxide and oxygen in the water.
If you decide to install an air pump
Considering all the facts mentioned above if you still chose to install the air pump amongst all the necessary equipment in your fish tank then it would be for the two reasons.
1) Creating an amazing visual display of air bubbles flowing upwards
2) Encouraging easy exchange of gases at the top surface of water by agitating it’s surface.
When you pick up an air pump it is necessary that it capable to handle the water capacity and the surface area that is being agitated when air escapes from the other end of the air tube.
If the tank is too big and pump too small to handle all the surface area, then obviously the quantity of air forced will not be sufficient to encourage enough oxygen exchange in the water. In that case you may require a bigger air pump or two air pumps.
The air pump equipment has 4 parts
1) Power cable
2) The pump casing
3) Air tube that gets submerged in the water
4) Air stone (sometimes not supplied with the air pump)
The pump has vibrating parts in it and some owners complain that this creates vibrations in the fish tank because this pump may sit on the same table surface as that of the fish tank.
Many times this creates humming or annoying sound all the time when the pump is running. Many pumps have rubber legs to absorb these vibrations. But it has been observed that in spite of these rubber legs that are meant to absorb vibrations the humming sound is still present in most case and that annoys many people.
The simple solution to this is to wrap the pump in a thick cloth and keep it on table surface so that the cloth takes care of all the vibrations.
The vibrations caused by the pump can have negative effect on the tank a well. Fish are very sensitive to vibrations of all sorts and if not taken care of this can lead to fish getting stressed after some time. If you are not in a position to reduce or eliminate the vibrations then the other solution is to change it’s place from the same table to a neabry surface that is not shared by the tank itself.
How long the air pump should be kept on?
The answer to this question completely depends on the size of the tank. As explained above the air pump provides fresh outside air through a tube into the tank. This air travels upwards agitating water surface and encourages gas exchange at the top.
If you find that fish are gasping for air even after installing an air pump then obviously you’ll need to keep it running for at least 6 to 8 hours. Depending upon the size of the tank a combination of air pump and powerheads must be installed so that the purpose of gas exchange is maintained and fresh oxygen is always getting mixed in the water from surroundings.
If the air pump is noisy with a hissing noise then you can turn it off at night hours and start them running during day hours. Many people prefer turning off the air pump at night hours because the filtration system takes care of water circulation and the new water brings in some amount of fresh oxygen with it into the tank.
The only problem turning air pump off at night hours is that you might forget to turn it on in the morning. However this can easily be handled with a timer facility if you have one installed.
How do you oxygenate a fish tank without a pump?
Now if you are not a big fan of installing an air pump then there are some other means to do it as well. (Read this article)
Some other ways to do this are
1) Installing powerheads that agitate the water surface. Normally these are installed at the upper layers of the water facing upwards and they blow water surface increasing it’s surface area encouraging exchange of beneficial gases.
2) Aquarium wave makers are similar to powerheads and can be used for the same purpose of agitating water surface.
3) Another way to add oxygen to an aquarium is to add live aquatic plants. Plants consume carbon dioxide and release oxygen into water. However this method does not give fast results and requires careful study of a planted tank.
4) Spray bars are installed where a canister filer is installed on the tank. The outlet of the filter is fixed to a tube with holes in it. The incoming water is then released from the serial holes along the upper surface of the water agitating it’s surface and encourage gas exchange.
How long can fish survive without air pump?
In worst conditions if your air pump system breaks down then it’s not something that you should take lightly. You must have a stand by air pump ready to be installed on the tank within an hour and get things going.
However if you don’t have one ready with you then at the most fish can survive without it for 2 days. After that the dissolved oxygen will start to decrease and you’ll see fish start gasping for air.
There will be a panic situation when your air pump and filter both break down at the same time. This can happen if you have an electricity failure in your residential area. Even if you have a faulty air pump that stop running, water filer will do the job of circulating water and bringing in fresh oxygen filled water into the tank.
However the exchanges of gases that takes place at the top layers of the water surface is the best way to ring in fresh oxygen in your fish tank.
Does a 5 gallon tank need an air pump?
First let’s check the measurements of a 5 gallon fish tank.
It would measure about 16 inches X 8 inches X 10 inches. SO you can see it’s a relative small tank. If you have a filter installed then you probably don’t need an air pump for this tank as far as there is enough oxygen in the tank. No matter how small your tank is there is no substitute for an aquarium filter though.
Does a 10 gallon tank need an air pump?
Just like a 5 gallon tank above, first let’s check size of a 10 gallon tank and it would be about 20 inches X 10 inches x 12 inches.
In such a tank which is not too big or too small you can install an air pump and see if the water surface it is breaking is enough for gas exchange or not. The primary function of an air pump is to agitate sufficient surface area of the water at top, so that beneficial gases are getting exchanged easily. If you have a good quality filtration system running all the time, then you don’t need an air pump.
The only reason why you would require it is it creates an awesome display of bubble flowing upwards. Many fish tank owners like this as a decorating item.
How do I know if my aquarium has enough oxygen?
The best way to know if your tank has enough oxygen dissolved in the water is to observe fish behavior. Fish will always show you visible signals through their behavior if something is wrong in the environment. When this go out of control then fish go under stress and you can identify this by observing their behavior.
The very first sign of a tank having less than enough oxygen is fish will start gasping for air at the top of the tank. To avoid these situations you must regularly check all the necessary equipment for proper functioning and if possible store standby models if your regular ones get broken.