Although this suggestion may come too late for some, it may help others, or anybody for next time. I live in an area that is famous for frequent power outtages, and we've becaome pretty power savvy, as our winters are pretty cold, and as i've been reading about you all with power issues right now, and sympathizing with you and your little fishie friends, i thought i'd share our power solution wih you all.
We have a power box, that we got from Canadian Tire. I think it's actually called "The Eliminator" power source. What you do is charge it up, and then when the power goes out, you can plug whatever you want into it. It has a bunch of regular 3 prong outlets, plus a buch of other kinds of holes to plug various other things into. If we needed to, we could bring it, and a space heater into one room and keep warm. We could also plug a power bar into it o run all the tank filters and whatnot, and the fish would never know the difference. It also has a light built right into it, and a radio too.
The charge will hold power with things running on it for about 2 days, so in case a power outtage goes longer than that, we have a solar panel that we can use to charge it back up again, or to run continuous power to the power source. It also is of "The Eliminator" brand, and we also got it from Canadia Tire. I'm sure you could get it at other hardware tpe stores as well. My husband uses the whole system on a regular basis to run our backyard astronomy observatory. But in case of a power failure, we can use it in the house.
I hope this info helps someone, somewhere!
Dana.