I agree with them being the main food source but when they are all 6 inches they are competing with the bass for food. I am going to start feeding pellets to help the food chain. I have no aeration and there is some grass and weed growth id say just perfect not too much and enough for some cover. The water is perfect clarity wise too.
YMMV, but I'm not having any crappie overpopulation in my 1.5a pond, so they can be balanced. I keep the weeds in check, maybe that helps. I bet BC population would explode if I had lots of cover. My BG and LMB are very healthy, my BC are a little on the thin side. I only catch 30-40 a year and take them all out. I have tons of crawfish, and find them in the gullets of most of my LMB. I find mostly shrimp in the gullets of the BC and BG, with some crawfish. I find only an occasional BG in the gullets of my LMB and BC.