3'-4' IS shallow and you will be constantly battling weed problems. The pond may get too hot for the HSB, but I don't think it'd hurt to throw 15-20 in there and see if they make it. You probably won't see them for the first year or two if they do make it.

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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).