Mold on the shell of crab

Question
Hi - I hope you can help me.  We have just purchased two cute little hermit crabs (within the last week, from the Jersey Shore). We have them in an cage that is wire so they can climb.  The cage is about 12 inches round and I plan on getting an aquarium.  However, I'm feeling very guilty, because I just noticed this morning that one has a black mold growing on him (or her).  It's on the shell, not the crab.  I have cleaned the cage as best I can, and right now they are in a cardboard box with some sand and toys and of course food and water. What should I do to get it off.  The only thing I know that kills mold is bleach, and obviously, I'm not going to clean him with that!  Can you help?  Thank you so much - Kris

Answer
Are you sure it is mold? Black algae type stuff isn't that uncommon and is harmless. If you are sure it's mold, get some oceanic or instant ocean salt water mix. Mix double strength and use an old toothbrush dipped in the salt solution to scrub at the shell. that should do the job. Don't work for more than a few minutes at a time.