The tires will be spawning habitat for the CC. If your goal is to grow large LMB, I wouldn't stock them. Any food that they potentially take away from the LMB is the downside.

Once they get around 3#, they start eating fish. So, it's like having more LMB in the pond.

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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).