I talked to Bob Lusk who has the advantage of knowing our lake and how we feed and he thinks it is bad or old moldy food pellets still left in the feeder from the winter. We just started feeding so it makes sense, although my assistant(74 year old father) swears he didn't start feeding until Sunday and the fish started dying on Saturday. We have not seen anymore dead ones so I don't think I have a huge problem. Thanks for your help guys.