I'm not sure if a peppermint shrimp would actually eat the worm itself, but I had to remove my Feather duster worm from my tank. The peppermint shrimps and my cleaner shrimp wouldn't leave it alone. I found out later that they where eating the mucus or something off the worm. They would "ruffle" and pick at the "feather" and it would go in it's tube, pulling the legs of the shrimp with it. The shrimp would get loose, and come back and mess with it again.
Not sure how often this happens, but I can't keep any kind of feather duster in the tank with the 5 shrimp. I even tried spot feeding the shrimp on a regular basis, and they still messed with the feather duster.:rolleye1: