That's a thin CC!

Your pond is very predator heavy, and they are eating every available fish that they can fit in their mouths to survive.

Heck, even the Ducks seem tame!

www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).