I dunno. It has a shiny shell like a cowry, but I don't see any of the mantle expanding over the shell. That tentacle-mouth is pure Nassarius, but the shell doesn't look like any Nassarius I've seen. Just for fun, I'll throw my vote in with the conch crowd.
QUOTE]<a href=showthread.php?s=&postid=15413532#post15413532 target=_blank>Originally posted</a> by pagojoe Nah, it's a marginellid, which does have a mantle like a cowry. They are predator/scavengers, and will feed on meaty leftovers as well as sometimes killing other tiny animals in your tank. Yours likes a bit elongated to be Prunum apicinum, but I think that's what it probably is anyway.