I was away when the power transformer blew due to a mylar baloon. I had a generator but it was in garage and pull start. My 225g took at hit for sure back in '09. Fish have a good chance of survival, coral not so much in my experiences.
Now I have 300ah battery back up, a Vectra M2 dc pump and the battery back up booster as well as Tunze powerheads on a separate battery back up. Apex is on the backup battery as well. My Champion generator is in the back yard with a cord ready to go. I may switch it out for a dual fuel unit and see if I can get it to run off natural gas.
I was thinking about a closed loop titanium heating coil using a hot water recirculating system off an inverter.
Last year a drunk took out a power pole on Orangethorpe. In 2 hours my temps dropped from 78 to 70, I started warming water on the gas stove and poured it into the tank. My generator is a bit too loud to run all night. I should just get a 700watt inverter and power it off my truck for electric heaters if something like that happens again.