Hi! My name is Denise and I have just purchased 2 hermit crabs on Friday. I have them in a 10 gal tank with all the accessories needed (food dish, water dish with sponge, calcium shell, climbing toys) including 2 extra shells. One if my crabs has been changing shells several times a day! He has been in both extra shells and then moved back into his original shell, then into one of the extras etc..Is this normal? Does this mean he does not like any of them? Should I go and get different ones?