Yeah, I'm not worried about carbon monoxide at all. I would be worried that I'd do something wrong and make the canister explode or something! That may be for farther down the line. For now I've got a box of "eco friendly ethanol chafing dish warmers" on the way, and they should do it. They were not terribly expensive. When they get here I'll fire one up and see how well it works. I do remember that the last time we had a power outage it was making me crazy - for the entire time, all I wanted was a cup of tea and I couldn't have one. Didn't want one BEFORE the power went out, but only because the power went out.... And if they don't work well I'm not out too much money. I could always use them to start a campfire.
I sorted out the aquarium problem, though. Kinda. I have large freezer bags. Which could be filled with water and then held close to us under a blanket. Human body temperature is warmer than the aquariums need to be (I keep them at about 75F) so if wrapping them in heavy towels doesn't keep the temperature from dropping too much we can warm bags of water and then float them in the tank. And I could also use some of the heat packs that I get for wearing on my back, I guess. Just set them under the towels against the glass....