Alrighty so.... UPDATE!!!
I have now had a crab in my tank for over two days and he is happy. He is a very large hermit. Very carnivorous too... I originally had him back when I first started up my 45 gal. He was my first purchase... I loved him til he eat my emerald crabs and so I traded him to an LFS. Well over a month later, I was at the LFS and he pointed to one of those tiny tiny little cubes that is part of the over flow system or the fuge or whatever and said he put my crab in there and forgot about him and hadn't fed him or anything. I felt aweful so I brought him home again and decided he can go in the 24gal and I won't put anything else in there except possibly some snails!! BUT he is living which mean.... YAY no copper!!!!