There are many species of hermit crab but generally there are 2 kinds, In Taiwan you can find both land and aquatic hermit crab. Aquatic hermit crab are smaller and more colourful. The new fave right now is keeping hermit crab as pet however before you purchase a new pet, please watch this vid and think about it. There is a good website that gives you a proper guide on hermit crab as pet.
There is a new research studies indicating that crab do feel and remember pain on CNN