Make sure none of your filter media dries out if u happen to have an HOB
filter. If you have a canister filter, you might wanna dump out the water that's been sitting in it when the power comes back, I read something a while back about the bacteria breaking things down in a way that produces something bad.. I know that's so vague it sounds silly, but it couldn't hurt. Be sure to keep it especially oxygenated if you have plants or an overstocked tank or if the water gets very hot. All factors that require more oxygen.