Unfortunately, for the moment, the highway is flooded to Westport Washington and the only way to save the fish is with some kind of local power source.
If possible, rig a 12 volt to 120-volt inverter from your car battery to the aquarium. A 400-watt unit will support a 300-watt heater, a small Rio 2500 water pump drawing 65 watts and an air pump drawing about 8 watts.
Four hundred watts of 115-volt power is equal to about (400/120) 3.4 Amps. Convert amps to 12-volt battery power and you have a battery power draw of about 10 times or 34 amps. Most car batteries will deliver in the range of 80-120 Amp hours before running down.
Most cars have a 55-75 Amp hour alternator/charger, which can easily keep up with the inverter power draw.
Last year when the power in the Seattle Washington area was out for 4 days at my home I ran my car engine almost continuously at idle to keep up with my 700-watt inverter power draw. Every few hours I increased the engine speed for a minute or two just to be sure it was pumping oil and not over heating. My fuel consumption at idle was in the range of 5-8 gallons per 24-hour period.
With this system, I supported the heat, filters and pump requirements on a dozen aquariums although not all at one time. I ran each of the four systems for 2-4 hour periods and then switch to another tank system. Yes, I was going steady and got very little sleep but no fish were lost and no tank got below 69 degrees.
I how have a battery start generator as nothing less would support the pumps and heaters on my just finished 8,000 gallon outdoor aquarium.