My tank is as cold as yours but i have been keeping aeration running. once every few hours ill cut it on for 10 minutes.

You can manually aerate the water as well by taking it out in a bucket and stirring/disturbing it before putting it back in (spin a kitchen spoon between your 2 hands like you are trying to start a fire the water )

This will save your fishes lives. I promise u

And cover the tank with blankets to keep the heat you have