How to Manually Generate Oxygen in Aquariums

A Simple Solution

air bubbles in aquarium

manannan_alias_fanch / Flickr / CC BY 2.0

In a power outage, an aquarium is safe for some time without filtration, but the inhabitants cannot survive for very long without the oxygen normally added by the powered air pump. You can manually add oxygen easily if you do not have a battery-operated air pump or an emergency power source to run one. The manual method also helps keep the water circulating. Learn what to do when the power goes out.

How to Manually Oxygenate Your Tank

You can add oxygen to your tank by slowly pouring water into it from some height above. The water will pick up air en route as well as drive oxygen into the tank water. How much oxygen is added depends on how high above the tank you pour the water and how many times you repeat this procedure. Here are the simple steps:

  1. Take any type of clean cup, pitcher, or another container, scoop out and fill it with aquarium water.
  2. Hold the filled container some distance above the aquarium, and pour the water back into the tank. Repeat this process numerous times.

There is no set rule on how often this should be done because every aquarium is different. You'll need to judge for yourself at what intervals each hour is going to be best for your system. When in doubt, go ahead and do it more. If the fish start coming to the surface gasping for air, it's definitely time to aerate some more.

illustration of how to create oxygen during a power outage

The Spruce / Wenjia Tang


  • Pouring water can stir up the substrate. To avoid this, place a small plate or bowl in the tank (one heavy enough to stay at the bottom) and pour the water over this area.
  • If you are using the floating hot water container method to manually generate heat in the aquarium, periodically pour some of the water over the top of the containers. Most of the heat generated from the floating containers will stay near the surface, so this is a good way to get the warm water circulated.

Battery-Powered Air Pumps

You may have battery-powered air pumps on hand for just such power outages. Note that most battery-powered air pumps are not very powerful and will not drive air very far into the tank. Be sure to test them regularly so you know whether or not they will be reliable in an emergency. The best and most reliable battery backup air pumps are the ones that run constantly on AC power, then automatically switch to the air pump's internal rechargeable battery when the power goes out. These work very well if you don't happen to be at home when the power goes out.

Test Your Water for Ammonia

If your system ends up being shut off for a long period of time, due to the lack of filtration it's important to periodically test the water for any sign of ammonia. If ammonia does start showing up, you can be ready to handle the situation to prevent ammonia poisoning by having an ammonia-reducing product such as Kordon's AmQuel on hand.