It’s not just your garden ponds you should be thinking of guys. If you are a club or fishery own who own small shallow ponds, pools, etc, it now time to get the sledgehammer out and brake some holes in the ice near the side (not out on the ice, to dangerous!) to let the toxic gases out, and air/oxygen in.
It might be worth giving the water a vigorous stir with a paddle or a shovel for a few minutes to put some dissolved oxygen back into the water.