This is my guess related to the Mpemba effect
Picture Bambi on a lake in early winter. What would be a way to make this lake ice covered. Safe for both land animals and fish.
I think a dual approach would work better. What if the ice at certain temperatures sucks heat from the air to the below water lake mass. Like a heat pump or a peltier element. This could perhaps save the fish in winter time.
Then for land animals. I guess we get Near Surface Air Cooling which should help in generating strong fully covered ice. Here I speculate that heat is drawn from the air near the surface. Making it like a freezer run by an air conditioner.
So the idea behind this speculation is that the freezing method of water should be safe for life.