First step is to call the power company to determine whether they have a restoration estimate. If it is to be a sub 2 hour outage, I'd not worry. Beyond that, oxygen levels are more problematic than temperature. Manually aerate the water periodically. If temp goes below 75 or so, then you might want to start to worry, but with an insulating blanket, shouldn't drop all that quickly.
In the future, at least have a battery-operated air pump on hand. A battery backup for a power head is also a good idea, as is a portable generator.