I have caught YP at Lake Simcoe in Ontario and packed them in ice chips for the ride home to PA. We usually fished 3 days when ice fishing and always had fish re-animate once dumped in the utility sink at home. I know some of those fish had been out of the water for 2-3 days and still came back to life, albiet with limited vigor, but they swam upright on their own. I have always marveled at that.