My pincushion urchin has been showing signs of stress for about a week. I did a water change and I think I messed up the salinity and made it too low. He spawned and then stopped moving around the tank. His little grippers and spines would move, he would react when touched, he just would not move from his spot. Today, I saw that one of his spines had fallen off. I know that’s a bad sign so I did another water change today. Checked the parameters and salinity. All is well. He still has not moved from his spot. He still moves his spines and grippers and has not lost any more spines that I have noticed. Can he be saved or should I start funeral arrangements?