Thanks for the replies.

I find it unlikely it was a weather related event. As you mentioned Rod, it was only cold for a few days and definitely not cold enough to drastically lower water temps. I figure its either outside predators or them focused on the spawn.

@theo, the surface temperature at least is 72 degrees plus. Right now I just have a pool type thermometer in the pond, so I cannot specifically say what temps are in deeper water. I plan to get a real thermometer in the future, I was in Ace Hardware and picked one up on a whim.