I recently purchased 2 of these snails marketed as cerith snails. I've never owned ceriths or even seen them in person so I believed the sales person, stupidly. I've since found them constantly attached to my acan frags on the sand and it appears they're eating the flesh/skeletal structure on them... can anyone tell me what they think these are and should I take them back or feed them something special? They really dont move, like at all, besides to scoot over to my acans. Definitely dont bury themselves like ive read ceriths do. Thanks for the help!