I have a small pond, ~less then 1 acer and had about 25-28 large and small mouth bass i put in there last summer, some up to 20". they did well all summer and produced a bunch of babies. by eariy spring and the ice thawed out i found about 20 floaters and had to pick them out, total heartbreaker :'(. didnt see much action but then started to see schools of small fish swimming around this summer. i threw in another dozen decent size fish over this summer and they all have been doing well. they will follow me around the edge in a giant school and take what ever i throw in at them; frogs, meat, crayfish, baby mice, snakes(even 12"+ they will play tug-o-war with) so i really dont want to loose these guys.

Im not sure why this could of been happening, the problem over winter time. some people mentioned that i need to keep the ice broken so gases can escape. should i be pumping air under the ice or keep a large area of open flowing water? we already have 6"+ of ice and need to figure something out so i dont come into the spring with another tragedy.

If anyone has any advice it would be greatly appreciated.

Wow, talk about timing!  I just posted a brand new article that addresses this very issue:  http://www.bassresource.com/fish_biology/winter-fish-kill.html

Enjoy!

Indeed Glenn, hope everything goes well for you this winter