Shad, for blues. That is what they eat most of the time. They are kinda like striped bass as far as diet goes. Flatheads, I have caught big ones on whole dead shad in rivers.The shad needs to be a big one, like 8 or 10 inches long. The best bait for them though is a nice lively hand sized blue gill. I like to trim the tail fin a little. It seems to keep them from dislodging the weight from the bottom of the river. The reason for this is I fish downed trees and logs in the river, wich makes bait placement key. BIG BAIT- BIG FISH