From the fish description, it sounds like it is light on forage and heavy on predators. An e-shock survey will tell you for sure. Remember, an angling survey just surveys the fish that will bite, an electroshock survey will show you the fish that won't bite too.

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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).