Hi, my urchin has been losing spines, ive just noticed quite a few on the sand bed. I put it down to either he's hungry or possible salinity shock when my ATO put a little bit too much water into the tank (but I think he's hungry). I only just noticed them today, so its still quite new. The other thing is, he was sitting on one of my corals, so I ticked him off by pushing him off of the coral, to which he quickly scurried away. I fed him some nori seaweed which he took thankfully, but is there hope? Will he be okay???