I have had a 4 day power out before when I had a 72 gal tank.
Everthing made it, but a shrimp that someone had for a snack.
I kept the room dark, and used a turkey baster to blow air
into the tank every few hrs.
I now have a 180 and bought some battery powered air pumps.
From my experiance It seems like it can take getting cold a lot better than
getting hot. I have a fireplace so it will never get too cold in the room
I think they can handle more cold than you would realize.
I plan on adding a 12v battery and a small solar panel to power
my Tunze pumps someday (Tunze pump sare DC).
For Heat since I have a Gas HW heater I thougth about taking about
25-50 foot of tubeing like on a RODO unit and a faucet adapter that
I coul run hot water through.
I would hook the input of the hose to the kitchen faucet, and the output
would run down the drain. Then throw the tubing in the tank turn on the
faucet and watch therometer. Crude but it would work, and the wasted
hot water would be a small price to pay.
I tend to shy away from generators, in a long term power outage
gas is very hard to get.