There's never a 100% rule with Crappie, but I have noticed that Whites suspend more and seem to school in larger numbers. Blacks always remind me of bass, grass edges, and lay downs, but typically not in large numbers. One or two in a spot, then move on. Concentrations of baitfish (when you can find them) will always stack the Crappie thick, often with bass, stripe, gills, catfish and everything else.