Actually those are dove snails of the collumbellidae family.
I know, IPSF sells them as 'strombus grazers'- but they're not in the strombus family.
I actually already knew about this ...it reminds me of berghia nudibranchs, lettuce nudibranchs, etc., which are also incorrectly identified on numerous vendor and wholesale websites as well...once a name becomes popular on the internet, the incorrect information becomes accepted as the truth, irrespective of the true scientific name. I believe the popular Strombus grazers, which originated from IPSF, in Kona, Hawaii, are most likely Euplica varians, in the family Columbellidae, the dove snails. It is known as Momi in Hawaii, which translates to "pearl." The shells of this species are commonly used in leis in Ni'ihau. Euplica varians grows up to 11mm long. From what I have been told, IPSF, like many other vendors and wholesalers, are only in the business of selling stuff and not correcting scientific names ....so if everyone else calls them Strombus grazers, that is what they will continue to call them.
I have been breeding these snails since 2006 and they were sold to me as Strombus grazers from IPSF. They are very reef safe, and may breed in your reef as well.
Sorry to get the thread off topic. Looking forward to the January Kickoff meeting at Marion's pizza!