I do not keepthem, although I have cared for them in the LFS I used to work at. IMO, one of the problems associated with keeping a sea apple healthy is the water quality of the tank. Since they are filter feeders they require lots of feedings to stay healthy (several times per day, a constant source of phyto is best), this has a tendancy to degrade the water quality of your tank quickly. This causes other problems for the tank, which in turn causes you to fed less often. Then the animal slowly starves over the course of six months to a year. If you can find a way to feed them what they need....they can be very hardy. They also expell their stomachs when they are under stress, not just when they die.