There you are, sitting at home relaxing one evening as a gentle rain falls outside, adding to the calm as you watch your aquarium. Almost relaxed to the point of falling asleep, you are awakened by a flash of lightning and a crack of thunder as the storm becomes more intense. Suddenly, the house is plunged into the unexpected blackness of a power outage. You know the routine: light the candles, dig out the flashlight, and look outside to see if the neighbor’s power is out, the usual. Something then occurs to you, filling you with a sense of horror: the aquarium has no power! If you haven’t prepared in advance, panic ensues.
So, that might be a bit of an exaggeration, but if you have an aquarium filled with a thousand dollars worth of living things, it might not be too far from accurate. With some planning and preparation, any aquarist can be prepared to keep their fish alive during power outages, even for several days.
If you want to prepare in advance:
- Preparation for a power outage in advance is the best way to go, as it will give your fish the best chance of survival. It is likely you have some type of home emergency preparedness kit for humans; we recommend something similar for your aquarium.
- Picking up the appropriate number of battery-powered air pumps for your tank in advance and keeping them in an easy to get to location, with a couple of sets of fresh batteries, is a great way to go for many fish keepers, especially if your tank is lightly populated. If the tank is 38 gallons or less, generally one air pump will do the job. For larger tanks, two or sometimes three running at once would be recommended. Something else that has become popular with fish keepers in recent years is having a battery back up on their aquarium equipment. The type used for computers is commonly used, and if that route is chosen, be sure not to plug the lights in to the battery backed up outlets. Plug in only the necessities of filter and heater.
- If you have a large tank that uses a massive filtration system, consider keeping a smaller hang on the back or canister filter as a spare to run from the battery, rather than the primary filter. The battery backup method is really only intended to be used for short-term power loss, but it works very well. The length of time the battery will last depends on the power consumption of the filter and the size of the battery backup that is used. Naturally, there are gas powered generators that can be hooked up outside for those hobbyists who are of the grunting, “more power” variety.
If you haven’t prepared in advance (the guide for the rest of us):
- The first thing to remember: don’t panic. Most fish and invertebrates are pretty durable and can handle temperature changes and lack of filtration for short periods without harmful effects. Unplug your light fixtures, filter and heater. Covering the tank will help to keep the fish calm, so they are not stressed by movement of people in the room. Fish that are not stressed out and are calm will not pollute their water as much, which will make things easier on them.
- Do not feed your fish during the first two days of a power outage. If the outage is only short-term, lasting one day or less then the lack of food will not hurt the fish. Adding food will just add to the pollution in the tank, which is what you want to avoid. If the power outage lasts into a third day, either skip feeding again or feed far less than usual.
- If the outage is lasting longer than just a few hours, it will be important to oxygenate the water. If you do not have a battery operated air pump available, then you will need to resort to manual methods. Manual methods of oxygenating the water would include using a bucket to scoop water out of the aquarium and then pour it back into the tank from a height of about 10 inches or so, or stirring the water rapidly back and forth in order to create turbulence. The idea is to break the surface of the water as much as possible and encourage water movement for oxygen exchange.
- As an absolute last resort, some folks will use a solution of 3% Hydrogen Peroxide to quickly raise the level of dissolved oxygen in the water. The dose is approximately 1cc of peroxide per 10 gallons of water once per hour. Using peroxide in your tank is going to damage the bacteria in your biological filter, so it should really only be used in the case of extreme emergency.
- Once the power is back on, it is important to do a series of small water changes on the tank over a couple of days. Some sources will recommend doing one large water change immediately after power is restored, but doing a small water change twice each day for two days will be less stressful on fish that have already undergone a great deal of stress. Typically, 10% of the water in the tank changed twice per day for two days should be enough to clear out the pollutants accumulated during a power outage, but each tank will vary so use a reliable water test kit to see where you stand.
- You should monitor your fish VERY closely for a few days after the power is restored to your aquarium. Be prepared to medicate your fish for ich, because it is likely that you will see an outbreak due to the stress your fish have just been through.
There are far more extensive discussions of power outage procedures available, but those listed above will be good for quick and simple reference to help your fish survive.