I caught a lot of carp mid-day during the summer and early fall on the Missouri river in Montana when I spent 6 years living in the hamlet of Cascade which sits right at the end of the quality or blue ribbon trout water of the Missouri.
The fly I used was an unweighted Black Ghost Zonker. It has yellow hackle fibers for a short tail; a black braided mylar tubing body; yellow hackle collar; and a whilte bunny strip tied zonker style. Use red or fl. red flat waxed nylon at the rear of the wing where it is tied to the end of the hook shank and black 6/0 to tie in the wing at the head of the fly. I used it is #2, 4, or 6. Fish it with a stacatto strip by using the rod tip and pullingthe tip down and back toward you, then strip in the slack and so on until the line is back at the rod tip.
I caught so many carp of 25 to 20 pounds that I had a friend accuse me of being addicted to carp fishing. He also got into the habbit of fishing for them at mid-day and used the same Black Ghost Zonker.
Give it a go, I think you'll like the results.