Well it seems like your doing things right assuming your water is in good shape, but to be honest they are very, very tough. I had a huge bobbit worm munching on mine at night and during the day he would still open up, a little smaller than before, but still open up. Hopefully it was just chance he is shedding right when you got him! BTLDreef said that she thought it was shedding so I would def. trust her opinion.