We put "washed pea gravel" in a few ponds, it varied from 1/8"-3/8" in diameter and SMB, LMB, BG, RES all use it for spawning.

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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).