personally i think you should go with both Golden Shiners and Threadfin Shad. You COULD have Gizzards but i would only use it on a pond with some monster bass, im talking a pond 5+ years old with some big fish or if your goign to have people electrofish it yearly. Bluegill and Readear sunfish wont sustain a bass population for that long so i would add
Golden Shiners
Threadfin Shad
Fathead Minnows
Crawfish