Decomposition and gassing to the point a fish will float takes a lot longer in colder temps. When I had my RES winter kill in 2017 at ice out it took a week to ten days before I started seeing any floaters. I checked the pond daily and it took eight weeks before I quit finding a few floaters every time I checked the pond. The last two weeks they were getting pretty decomposed when I found them floating, skin missing off of their face, that sort of thing. I suspect that the majority of the RES that died never floated at all. I picked up 128 RES over eight weeks and I suspect the number that actually died were four times that amount.
