A spin on an earlier idea in the thread -
Get a safety pin, and some fishing line.
Pin a piece of shrimp onto the safety pin. Close the safety pin. Tie some fishing line onto the safety pin.
Dangle it in front of the fish, try to simulate a real fish.
I've gotten plenty of stubborn fish to eat this way. It's very non intrusive as well (lot less so then the coat hanger idea)
Hope it helps