molting question

Question
I bought three hermit crabs at a pet shop. I bought a small, medium, and large crab. The person that helped me at the pet shop informed me of different things I need to Care for them. I bought three extra shells, food, salt water conditioner, a brown mulch like flakes to keep the tank humid, sponge for filtered water for them to drink and dishes for the food and salt water. I kept my crabs in a 2 1/2 gallon tank. I used small rocks, like the ones used in fish tanks. As per the person at the pet shop he said it was ok to use. I decorated it with plastic trees and bushes so they can climb and hide. I kept my crabs it my bathroom. Every time I took a shower I took them out of the tank so they can walk on the floor, since the bathroom was humid because of the steam. To me they were very active. They liked to walk & climb. A little over a month my largest crab was spending most of its time near the food and water. A few days after I did see that he had shed out of his skin. He was doing this inside a plastic cave he had in the tank. A few weeks had gone by and he is not moving and seems dried. I called the pet store, they suggested for me to remove him from the other crabs because he was molting. They explained what molting was. So I did. I made him a separate tank with the same things I used for the other tank. Half of him is still in his shell, the other half is hanging out. He has been this way for almost two months. The tank doesn't smell as if he has died. Now my medium size crab has not been moving for five days now. There was no sign of it shedding skin. It too has half of it's body inside its shell, the other half is hanging. The smallest seems to be ok. I've had these crabs for almost eight months. Has my largest crab died or is it still molting? If he is still molting how much longer will he be this way? For my medium size crab, is it molting too? Can it molt without shedding from its skin. What's the longest a crab molt?

Answer
The large one should not still be molting at this time, in general, crabs only take a maximum of 2 months to molt, and usually it's only the GIANT ones (baseball sized) that take that long. If the tank doesn't smell he is most likely not dead either. He could be under stress. The petstore people, although genuine in wanting to help you have mostly set you up for molting failure. You should not use gravel in a crab tank for precisely this reason and because gravel scratches and cracks hermit crab exoskeletons, exposing them to infection and parasites. Hermit crabs will dig to protect themselves during molting time and they can't dig in gravel good enough to help them. Sand would be a far superior choice in this regard. The crab may just be extremely stressed out from not being able to protect himself during the molting time. If he doesn't make any moves to protect himself when you pass by or attempt to pick him up (doesn't go back into the shell) He is most likely ill from the stress. 3 crabs in 2.5 gallon tanks is also not a good combo because although crabs like company, they don't like to be crowded. If you want to give your crabs a better outlook on life, you should get a 10 gallon tank and try to find a plexiglass or glass lid for it, some fish aquarium stores sell glass lids, or you can get a sheet of plexiglass cut for you at a home improvement store. You didn't mention any heat source either. Bathrooms are notoriously chilly places and your crabs will need some sort of heat source to remain healthy. You can use a heat lamp wth a glass lid or you can get an under the tank heater to stick to the underside of your 10 gallon tank. Either way, just make sure the bedding (the brown chips) stays wet and it will boost the humidity, the sand doesn't have to be wet all the time, but you should make sure it's moist enough to stick together in a ball if you squeeze it in your fist when a crab starts to molt, so it can bury itself. The amount of sand and bedding you need will be about 2 or 3 inches, depending on the size of your larger crab, the sand and bedding should be slightly deeper than he is tall including his shell.... Oh and one more tip, you could probably do wth more shells, crabs are very pick and only having one shell choice each will make them unhappy. Each crab should at least have 2 or 3 shells EACH to choose from.