In the words of Bill Cody, it all depends. :-)
Crappie diets will vary depending on location, water body size, available prey base, etc. White crappies tend to be a little more piscivorous. Black crappies seem able to do better on zooplankton and aquatic insects, even at large crappie sizes. Don't get me wrong -- black crappies can also be very piscivorous. Hybrids will be intermediate?? Maybe??
In large water bodies with gizzard shad or threadfin shad, crappies will really prey on shad when the shad are the right size. In a pond with only largemouth bass and black crappies in Kansas, we did monthly food habits on the 12 inch black crappies from February to December. They ate zooplankton and aquatic insects. They were low density and fast growing because the abundant small LMB really thinned them. They had full stomachs and high Wr values.
Will crappies eat bluegill. My guess is that they will eat some small bluegills when those small bluegills are just the right size for the crappies in question. However, most of what your crappies eat will depend on what is in your pond. Predator fish tend to eat what is abundant and vulnerable.
Hopefully we can get a little more input from others.
