Ilyanassa obsoleta are what was formerly Nassarius obsoletus. They are obviously not Nassarius, but are in the same group and perform the same functions in a reef ecosystem as Nassarius. When I discussed the issue with Ron Shimek, his objection was simply that they would die in a warm system....but I have found that they survive for years.They are scavengers, climbing the glass and burying in the sand, emerging as soon as they detect food in the water. I have kept Ilyanassa snails in my reef systems for over 10 years without problems, and are excellent clean-up snails. They survive for years...as intertidal organisms they are adapted to wide swings in salinity and temperature, and can even be added to a reef tank without acclimating. Yes, they are hosts for the cercariae that cause swimmer's itch, however these parasites cannot survive full strength ocean salinity. While I occasionally do get swimmers itch when I wade in the creeks while fishing, it is only a) on an outgoing tide, and b) after heavy rains have added fresh water to the tidal system. FWIW, the sg in these tidal creeks is usually about 1.017, while my reef system is kept at 1.126. I have never had issues from these snails in my tank, and, as I've said, I have been using them for well over a decade.