How can you take care of a periwinkle from the snail family?

If you are considering putting periwinkles into your saltwater reef tank, don't. Though they are of no danger to your inhabitants, periwinkles are cold water snails. Yes, they can live in 82 degree tide pools for limited amounts of time, but they will NOT survive more than 3 months in your aquarium. Periwinkles are typically bought in bulk online and I'm sure you can imagine what happens to your marine ecosystem when 50-100 snails die within a week of each other.