Lake turnover is a complicated issue and different for every lake. Some lakes can have excellent fishing while there is still some ice and for a few days until the lake starts mixing and the O2 gets spread thinly. The theory is that the bottom of the lake is warmer from weed degeneration and when the top and bottom are similar temps then they readily mix. However, if you have a lake subject to a lot of wind, the mixing happens right away. The fish become dormant while they try to survive with low levels of O2. Some may die.
This year I did not get the pleasure of good fishing right after ice-off but now it is starting to turn on.
Caught about 6 like above in a couple of hours at a small brookie lake in Calabogie. They were feeding in one area close to shore. Most of the rises were the recently stocked fish and I had quite a few on small dries. I also had on a chironomid dropper and that was getting the older fish. Brook Trout are very social and mix together readily. Where there is one, there are usually more. This hatch of midges were quite large.
Nice to be 'back in the saddle'.