If the power is going to be off for any length of time, don't feed the fish until the power comes back on. Without a filter to keep the water clean, or light for plants to photosynthesise and use nutrients, any food will quickly produce ammonia that will kill the fish. Healthy adult fish can go for weeks or even months without food and a few days without food is not going to affect them at all (unless they are babies).
If you know there is going to be a power outage, do a big water change and gravel clean the day before, or even a few hours before. This means the aquarium will be cleaner with less rotting gunk in it and fewer bad bacteria to consume the oxygen in the water.
Most of the time you don't get any notification of a power outage and you wake up to no power.
Battery air pumps can keep oxygen levels high. They can also be used to run air operated filters (sponge, box or undergravel filters).
If you have power filters, clean the filter media in a bucket of aquarium water and then put the media in the aquarium. There will be more oxygen in the aquarium water and this will keep the beneficial filter bacteria alive for longer. If you have a battery powered air pump pushing air into the tank, it will keep the filter bacteria alive until the power comes back on. At which time you can reasemble the filter and get it going again.
If the power is only going to be off for a few hours and you have external power filters, you can do the following.
For HOB (hang on back) style power filters, you can take a bucket of tank water and pour it into the top of the filter and let the water flow through the filter and back into the tank. Do this once or twice an hour and the bacteria will be fine. This will also aerate the aquarium water a bit as the water overflows back into the tank.
For an external canister filter, take the outlet (return) hose from the aquarium and put it in a clean fish bucket. Let the bucket fill with water and then put the outlet hose back in the tank. The bucket of water that came out of the filter can be poured back into the aquarium. Doing this once or twice an hour will keep fresh oxygenated water flowing through the filter and keep the beneficial filter bacteria alive.
If filters are cleaned regularly (at least once a month for any established filters), there will be less gunk in them and there will be more oxygen for the good bacteria.
If you have regular power failures, then think about doing 50% water changes every couple of days. This will ensure the aquarium is kept nice and clean and if there is a power outage, the tank will be cleaner and the fish should be able to survive longer without power.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.
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I used to have some 3 inch diameter pvc pipe that ran along the ground next to the wall in my fish room. It had a couple of pipes that stood up about a foot and I used a gravel cleaner to drain water from the tanks into the pvc pipe. The water then flowed outside onto the lawn.
I had triple tier stands and filled the top aquariums with tap water via a hose. (The lower tanks had fish in). I let the water aerate and dechlorinate until I did water changes. Then drained water from the top tanks into the lower tanks with a hose that had a tap on it.
There was minimal effort from me and I didn't have to bend down or drag hoses around. This helped a lot when I was recovering from a car accident. Perhaps you could do something similar so you can enjoy the fish more and not have to do as much strenuous movement. The initial outlay would be a bit more but the end result makes it really easy to do water changes.
You’re most welcome!
