I think water flow plays a big part in successful trapping. The fish/crawdad can follow the bait scent from downstream, but if the cone is facing upstream they won't be able to find the entrance to the trap.

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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).