CoachB, do you have RES or PS in the pond? If not, you may want to look into getting some. You are at the Northern edge of RES survival, so they may be a crapshoot.

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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).