This guy has been in my tank for a while, it just occured on me it could be a Whelk. He spends most of his time in a cubby on the rock, i never see him on the glass or out and about, just lurking haha. Any ideas if it is a predatory Whelk or how I can tell if it is a Whelk would be appreciated, thanks
http://www.youtube.com/watch?v=F_rdNbFJgKQ
http://www.youtube.com/watch?v=F_rdNbFJgKQ