HOW TO KEEP YOUR TANK SAFE DURING A POWER OUTAGE
When the power goes out, that means that your aquarium heater won’t be working and the temperature in your aquarium could drop significantly, especially in the winter months. Glass is not very efficient for retaining heat so the temperature could drop quickly and your fish could suffer the consequences. To minimize heat loss, cover your tank with a blanket to trap in as much heat as possible. Make sure you unplug your lighting system before you cover the tank with a blanket because certain lighting systems might pose a fire hazard if they come back on while the tank is covered. Another option is to heat up some water on the stove and pour it into plastic bags or jugs and float them in the tank. If you use this method, make sure you don’t heat the water too much or it could be dangerous for your fish.
Without a filter running, the oxygen supply in your tank can rapidly decrease and your fish could suffocate if the levels drop too low. The best thing you can do is to buy a battery-powered air pump and use it to run an airstone to create some water movement in your tank. If you don’t have a back-up pump then you can do this by hand. Simply take a cup and fill it with tank water then dump it back into the tank to produce water movement and air bubbles. Another option is to hook up a piece of airline tubing to the type of hand pump used to inflate bicycle tires. Though this option may not introduce much oxygen into the tank, some level of water movement will be beneficial.
In addition to the steps already discussed, there are a few other simple things you can do during a power outage to minimize the damage. For one thing, you should avoid feeding your fish during a power outage because the waste they produce (along with any uneaten fish food) will accumulate in the substrate and impact your water quality. Aquarium fish can survive for a full 3 to 5 days without food, so do not worry about any harm coming to your fish by withholding food. If you know that a storm is coming that will likely knock out your power, you should perform a large water change of 40% to 50% of the tank volume before the power goes out – this will help to negate the effects resulting from the loss of filtration.