Pretty Basic Question

[Average Fisherman]

Forgive me for my constant barrage of fairly basic questions. Today's edition revolves around what I pull in with my cast net. I know what mullet, lady fish, shrimp, etc. look like. But frequently I'll toss out the net and bring in several flat, whitish gray, 1-3" fish. What are these, and when they are that small, are they a usable bait? If so, is it the same basic Carolina or double drop rig you would use fishing mullet?