"I understand fish go deep given low BP (high skies), no wind, clearer water, etc."
Not neccessarily, depends on the time of year. You get a COLD, calm snap this time of year and the fish set up SHALLOW, alot of times in vegation or wood, whatever cover is available. You dont realize it because they become almost impossible to catch but they are there, I learned this valuable lesson last december, we had a huge front and cold snap. Caught MONSTERS in 1' of water for three straight blue-bird days. The only bad part was we caught them on minnows while crappie fishing. After reflecting on it, I bet they would have bit the FnF rigged real shallow, maybe...
As far as DO, once the thermcline breaks up and turnover begins, its role is insignificant, they will be with the bait.