First the good news.. My boss has sent me a text saying there will be no electricity at work tomorrow from 8.30 to 6.30 so we get the day off

Now the bad news.. She has two very large goldfish in a 64l tank which is far to small for them but that's another story.
Anyway, I'm not in work today and am worried about the effect on them. Will the bacteria in the filters die? Will the fish be okay? Should I go in tomorrow and do a water change? I can't get in today and nobody else there would be willing to do anything.
Edit
I just read the article on Power Cuts but it wasn't much help as a battery operated air pump is not an option.