Temps have been cold to freezing though, no ice on pond at all

We had severe winds on the 14th of Dec.

I don't disagree with Bob whatsoever as you obviously have some clinical signs of disease and your fish density sounds very high for such a small pond, but too me the obvious stressor was the severe high winds and cold temps that probably mixed and changed water temps drastically. Too quick a change in water temps is very stressful on fish. Disease problems are trigged by a stresser and to me it's obvious what it was, considering you folks had winds up to and past hurricane force with that freak storm. I believe some areas out there had 90 mile an hour winds?

I have seen my fish stressed out by rapid water temperature changes. Additonally since there were so many they many have gone into winter in a weakened state due to less then optimum feed for all of them.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.