Storms in the Midwest-

Some of it depends on the fish, I suppose. Bettas can be transported- actually, many people do use bin type houseing for them. Strong plastic bins can tolerate heaters (if in doubt, get a suction type and put it on a piece of slate on the bottom) - 10 gallon buckets can easily hold a running marineland magnum HOB filters, and totes can be used for other types of fish- rigged to suitability.

This shows a temporary goldfish setup I had (no heater needed in that warm room) that was made from scraps around the house:



Stores sell heating tape as well, or you can order it online and if you *have* to have fish in bowls there are heating pads you can buy to set them on.

You can heat fish temporarily by having them in a tank that is in a larger tote with a heating pad/blanket tucked around it and/or over the entire makeshift setup. If absolutely necessary, you can use the tote the tank sits in as a bath itself, adding warm water around the tank in order to help maintain temps without shocking the fish with temp changes in their immediate environment.

It's always good to have aquarium salt onhand, as it does help in situations of stress, ammonia burns or with other small nicks/issues including ich that can come up in unexpected circumstances.

I keep emergency supplies, noteably the above- along with medications, breather bags, rubber bands, foods, new steralite bins (lidded) and styrafoam coolers available at all times since I do live in an area prone to flooding and power outages.

If we have to evacuate I can bag the fish, gather their items and pull the filters out of the tanks for future use in temporary setups. Regular HOB filters (rectangular ones) dont work in buckets but will in totes. I also keep a fair ammount of air tubing, air pumps and sponge filters available because the sponges work great and are better than nothing.