_Cal_
Fish Crazy
it would keep the fish alive yeah, but it wouldn't solve the problem of the beneficial bacteria in your filters dying off.
once the power was restored you would basically be left with a "new tank" full of fish and a full cycle would have to ensue, which your fish would probably not survive .
But keeping the filter media wet would keep the bacteria alive. I dont really have power outages around where I live so no worries, the only time I even had a power outage the last 5 years was the massive blackout that consumed the northeast a couple years ago.