Back on January 6, after a big snowstorm (for this area anyhow, got between 12-15") and then arctic freeze with below zero air temps, power went out for 22 hours. I have no generator, but had 2 kerosene heaters I started up the following morning. Power went off around 7 that evening, and by 5 a.m., the house was 40 degrees. (In hind sight, I will in the future start up the heaters as soon as the power is off more than an hour, live and learn.)
Anyhow, the following day, with heaters going, temp in the house barely made it up to 50, and the fish in the tanks were feeling the cold.
I had 2 battery operated aerators, but figured that would chill the water more, and didn't use them. This is what I had to sit and watch happen while I had no way to help them out. I was certain both angels and the Archer fish were all dead.
I cleaned both tanks this past weekend, so I can finally show what they look like, and am happy to say that ALL of these fish survived. I did lose my two rummy nose tetras from the large tank, and the two green puffers from the brackish tank. But, learned that corys, plecos, killifish, mollies and my big Mono were none the worse for wear in the extreme cold. I will try to get that situation rectified so I don't have to worry again in the future, though.
The two tanks sit side by side, but where I sit in the evenings and on the weekends (if I'm in the house that is ...) is directly across from them, so get the most enjoyment from them this way.
In the brackish water tank, on the left, there are 3 different colors of Mollies - white, black and black/white. Also an Archer and a Mono (you can see the Mono in the back, behind the heater, where she hides, unless she's chasing the Archer).
The fish in the tropical 55 gal aquarium include two large angels (both that 'came back from the dead during the power outage'), a long finned Rosy Barb, 2 Killifish, 2 Clown Plecos, a Dojo Loach, 5 or 6 Cory Cats, Horseface Loach (hides in the gravel unless it's feeding time).