Only if it draws minnows to the tops. And even that would depend on what type of "minnows" your lake has. I really don't think the Crappie would be interested in feeding off the cake, so it would depend on what the cake does (molds, sours, swells/bursts, etc ??) as to what it would attract. And if it attracts catfish real good .... that might keep the Crappie away
... cp