Are Air Pumps Necessary For Fish Tanks?

Air pumps are not necessary if you have other filtration system in your aquarium that provides adequate water surface agitation for gas exchange. For example, if you have installed spray bar for filter to create water movement at the top then you don’t need air pump. But before you completely discard the idea of using air pump, here are few advantages of owning an air pump that you should consider.

Oxygenates the water

Water agitation at the surface increases the concentration of oxygen in water. When there is movement of water at the top, it increases the surface area over which oxygen is absorbed from air and carbon dioxide is released into air from aquarium water. Greater the surface area of the water, more it is in contact with the air for absorbing oxygen and expelling carbon dioxide. It is also important to note that water surface should not be stagnant for oxygen and carbon dioxide exchange to occur. Without surface agitation, process of gas exchange is very slow. For carbon dioxide to escape into air and for oxygen absorption, surface disruption is crucial. Air pump, exactly does that. It agitates the water surface thus facilitating better gas exchange and aquarium oxygenation.

Improvement in water circulation

Water at the surface is more oxygenated than water in the lower area of the tank. Air pumps circulate this highly oxygenated water from the surface to the bottom of tank and move water from lower bottom to the top. Water from the lower area of tank have higher carbon dioxide and less oxygen so when they reach at the surface it can release carbon dioxide and dissolve oxygen from air. Thus good water circulation (not surface agitation) plays key role in distributing oxygenated water in all area of fish tank.

Without good water movement, area close to heaters or chillers is going to be warmer or cooler than other area of aquarium. This can result in false reading of water temperature.

Air pump improves water circulation around heater and chiller ensuring that temperature of water is even in the entire aquarium.

Air pump may seem unnecessary if you already have filter that provides good water circulation, however, it is good practice to have extra air pump as backup in case your filter clogs or power outage occurs. Air pump will continue to keep water oxygenated and prevent any disaster that may unfold.

Sponge Filter / Corner Filter

You are going to need air pump if you use sponge filter. Sponge filters are simple and cheap but they are just as effective as more pricier and fancier filters. Sponge filter makes excellent choice for fish tanks that require low current filtration. However they are more suitable for smaller fish tanks.  Other downside of sponge filter is that it does not provide chemical filtration.

Corner filters are powered by air pump. It uses air pump to draw water through the filter. Corner filter requires lot of maintenance which can dissuade hobbyist from using it. Like sponge filter it is also more suited for smaller tanks.

Action Aquarium Ornaments / Air Stone

Action Aquarium ornaments like spinning wheels, treasure chest, volcano and many more are designed to be run by air pump. They make aquarium more lively and aesthetically pleasing. If you wish to operate these ornaments in your tank then you need to get air pump. Added benefit of having action ornaments is that bubbles produced by them can also enhance aeration in the aquarium.

Air stone produces stream of small bubbles when used with air pump. There is a common misconception that these bubbles increase oxygen level in water but in actuality it is the surface agitation caused by bubbles that increase the oxygenation of aquarium water.

Supplement Oxygen

Air pumps are effective equipment to remedy the threat of low oxygen level in water.

During summer when water warms up, concentration of dissolved oxygen can decline because warm water has lower capacity to hold oxygen. Air pump is going to be a very cheap and easy way to replenish oxygen in the water. Other options include powerhead or additional filter.

When you add new fish in your aquarium, there will be demand for extra oxygen. Air stone can introduce oxygen needed for fish tank by increasing water movement.

Be careful not to overcrowd your fish tank, it can deplete oxygen to critical level. In such case you are required to do large water change as well.

Hospital / Quarantine Tank

It is essential that you have a hospital tank( or quarantine tank) for treating sick fish or to quarantine new fish before adding them to your main tank otherwise new fish can introduce parasites that can cause catastrophic damage to your tank.

For hospital tank set up, low-flow filtration is better suited because sick fish may not be able to fight strong water current. Powerful filters can suck fish or cause injury to the fish.For this reason sponge filter is an excellent choice because of it’s safe and gentle flow. You can also add extra air stone to oxygenate hospital tank.

Final Thoughts

Air pumps are necessary

• if you are using filters (e.g. sponge filter) that require air pumps
• if you have aquarium ornaments animated by air pump

Adding air stone paired with air pump is beneficial regardless of what other filtration you have in your aquarium. Even if you deem the benefit of air pump will be minimal, it will increase the surface area of water(essential for effective gas exchange) and improve water circulation.