another way to tell is if it was still holding its nems. if there are ever nems in the shells hands, its him. if not. its his molt. its funny cuz this reef tank business can leave you with alot of ghostly remains, just dont wake your girl up telling her you lost a shrimp/crab until you know for sure LOL!! I woke up this am to half my coral banded shrimp.. or so i thought. Hes still fine hiding under a rock