What is the best bait for redfish while fishing of a dock in a river

Moving baits for me. Jigs, Mirrolures, jigs tipped with shrimp, Popping corks with a jig or shrimp, Johnson Silver spoon with a white curly tail. 

i have caught them using a chunk of crab and mirrolures but there arent very many reds in my area

We don't have many of them here, I've caught them on xraps while fishing for snook. On my redifsh trips I've used gold spoons, bucktails and jigging artificial shrimp.  Probably no bait surpasses live shrimp for almost all southern saltwater species.

My favorite is a jig tipped with a shrimp. Hook the shrimp in the tail so when the jig is sitting on the bottom the shrimp should have his head an legs sticking up.

Shrimp, pogie or mullet for live or cut bait

For artificials, try gulp shrimp on a jig head or under a popping cork