I've got a decorator crab in my tank and it did a pretty good job on the feather duster that I bought (I'd LOVE to have a colony of featherdusters in my tank like that)...
The Christmas Wrasse (Halichoeres ornatissimus) </em>will eat them in my experience and are marginally reef safe (will eat other snails, shrimp and crabs). However, they get pretty big. What size system do you have?