Yep, Common Carp is what it was. If you had 4 dead ones, I'll bet you have more. The Blue Heron is nice to watch, but they do eat a number of fish, and they will stab and sometimes kill fish larger than they can eat.

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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).