Just bought some "algae wafers" & "calcium/food mix blocks" for the Red Ramshorn snails & MTS I have just bought on eBay. I read that the Rabbit Snail also eats these and will not touch healthy plants if enough food is available. Seems to be conflicting info on they're feeding habits though.I remember reading that they prefer hard water and a ph over 7 to keep their shells healthy. They will murder most plants and may have parasites or some sort of leach I believe which can be treated. Sometimes when you introduce them into your aquarium females will give birth to babies due to a change in environment.
This is just from reading around a while ago and not first hand experience, but it should provide some points to research.