I purchased a cral banded shrimp about 3 weeks ago. Since then I started seeing some of my smaller snails dead lying in the sand. At first i though somethig was wrong with the parameters but everything is near perfect. Several days ago I lost my box fish. He was the only fish in there at the time. He didn't look beat up at all just pale white lying on the bottom. Later that day I can home and my urchin was dead. All his spike were ripped out. Now today I found a dead turbo snail. He didn't seem beat up either. The remaining snails have burried themselves deep into the sand almost as if thier hiding. Tested again and everything is good. All my corals are fully opened and seem very happy. Anyone ever seen anything like this before? When I first putthe shrimp in he attacked my starfish but I haven't had any issues with his since then. I spot feed him krill at least twice a week. Any input would be great.