That is a crappie and looks stunted with the large eye. You have what most fear when stocking crappie, I can now see where they can be an issue.

I put them in my small pond as well not knowing any better. I did stock Black Crappie which ended up being the black nose crappie, but I think even though they do not spawn as heavily as the White Crappie (or at least this is what I was told) I can still have issues.

Did you have any larger crappie that were dead?

Do you have a picture of the trap you are using?