Your aquarium’s environment is directly dependant on both you and the power source that allows key hardware to function, such as your lights, heaters, filters, circulation pumps, air pumps and skimmers. That said, the life within your aquarium requires a lot of support.

So, what happens when all of it is non- functional? What do you do in the case of a short- or long-term power outage?


The moment a power outage occurs, you must let common sense prevail and go into prevent mode. What you can help control you should act on. The temperature is an example. If it’s hot outside, make sure to close the blinds to reduce the effect of the sun. If it’s cold outside, windows should be shut. If you live in an area where longer power failures are not rare, then you can consider putting a thick plastic drop sheet over your aquarium and loosely securing it with some masking tape as plastic is a good insulator. Don’t forget to get your battery-powered aerators running before you do this.


Short-term power outages are usually of no major concern.

Those who keep marine aquariums with a sump should be wary of the right operational level. Be sure the water level increase within is contained when it is non-operational. A clearly-marked operational water line is always a good idea for any sump.

A back-up battery-driven air pump is also a good idea, especially for heavily-stocked aquariums. In case you don’t have one or have to take emergency measures because your fish are gasping or nervous, rapid stirring of the water’s surface will help oxygenate.


By the time you have surpassed 6 hours, you can consider the power outage to be long-term.

At this point, you may consider doing some partial water changes with warmer water if the temperature has dropped more than 5-6°F (2.5-3°C). Your back-up battery-powered aerators should be running. DO NOT FEED FISH DURING A POWER OUTAGE.

Filters can be removed and cleaned, then put back and connected to fittings. Wait until the power is restored to prime and start them up.

Give the media a light rinse and remove the bulk of any trapped debris. This will prevent any decomposition issues and formation of potentially harmful gases within the filter.

If the aquarium is heavily planted and well-stocked, you may want to remove a percentage of the fastest growing types of plants and place them in a bucket of water until power returns as plants do consume some oxygen during darkness. This is really only necessary in very heavily-planted aquariums.

Ultimately the only real and complete solution is to have a generator to provide power, at least to power filters and heaters. Lighting can remain off until regular power is restored.

If the aquarium is heavily stocked, it would be wise to take an ammonia and nitrite test to ensure all is well. A partial water change at this time would also be recommended.