You need to provide water with no chlorine or other additives. I use bottled low sodium drinking water for both their water dish and their bi-weekly baths. Change the food every other day and the water daily. Be sure to keep a piece of coral and sponge in the drinking water dish to help them crawl out. This also leaches calcium into the water which is needed by the crabs.
Provide a bath of lukewarm water which has been treated with "stress coat" (contains aloe vera). FMR and other crab lovers have shown this is beneficial to the crabs health. Don't bathe more than once or twice a week or the crabs may die. (I lost several because I was bathing them everyday.)
Conclusion
Crabs are easy-care pets if you provide for their basic needs. They will give you endless hours of enjoyment as you watch their climbing antics. One thing I find amusing is their single-mindedness. If they start out traveling in one direction, they will go OVER any object (including other crabs) that get in their way. They never seem willing to go around a barrier. I have several that will eat out of my hand and actually come out of their shell when they hear my voice. It's fun to watch them moving backwards and sideways almost as fast as they go forward.
For more information on the biology and care of hermit crabs, please visit Hermit Crab Care Page and join the hermies email group. You'll find many people who love hermies. They're always ready with lots of good advice.
Owning crabs and watching their shell changing habits has caused me to pick up my shell collecting hobby again even though it requires purchasing most of my shells. This evening, I just mail-ordered a gallon of shells for my hermies from Florida. Can't wait to see what they send me and how my little friends react. Thanks to my crabs, I also found an email discussion group just for shell collectors! Amazing what you can find on the internet.
Until next week, good gardening to you! Let me know if you decide to try out hermit crabs as pets. I'd love to hear from you in my discussion area.
