I recently purchased my soft shell and have discovered they didn't tell me his correct environment. Should have read up first but didn't! Anyway where i had stones and slate etc in his tank, trying to bury himself has caused damage to the shell. His back is shredding and he has white sores underneath. I have changed the environment to sand and smooth stones two weeks ago but his shell looks no better. Is there a medicine I can put in his water? I only have one 5 by 4 by 2 tank so can't really move him to another tank... Need advice quick please?