Besides the fish dying, what other things are affected by low d o in the winter? Does it kill crawfish, or any other small bugs or invertebrates? Does a bow that winterkills have a harder time with beneficial bacteria dying off and causing more muck buildup?
Enquiring minds would like to know.
Thanks for responding

In my experience everything took a hit. Two things seemed to survive better than anything else though, Fatheads and Scuds. Looking back now, before aeration, I think even the fatheads and scuds were dying as well just not as severe. After aeration I seem to have far more scuds and fatheads plus I see a lot more "bugs" than ever before.
Someone else may have a more eloquent answer, but here's my take on the bacteria. There are two types of bacteria, aerobic and anaerobic. Aerobic digests muck MUCH faster than Anaerobic. The more time your pond spends with low DO or, if your bottom water is anoxic, the more time you depend on anaerobic bacteria and it will never keep up with muck build up.

FH have very good low DO/poor water quality tolerance.

There is some evidence that BOW that experience winter kill tend to repeat the same process absent intervention (aeration or other).

Not sure about scuds but some crustaceans can survive those events.

I agree with wbuffetjr and ewest. Unless you have land lobsters, everything is going to be affected. All that decomposing matter on the bottom is going to create anaerobic conditions reaching further and further up the water column. The bottom of your pond is really critical to the quality of your water.

Speaking of crawfish I have only saw a few in the muck when I have been working in it. Do they not prefer abundance of muck, and when I am working in it it is very cold compared to the surface water six inches above. (Devoid of oxygen). Does that mean they cannot survive very well in it? I would love to have more of them. Are rocks only there to protect them from fish, or do they need them for another reason?