I came home from work today to see my clam completely withdrawn into his shell with the shell open. He is not responding to light or touch at all. I have 2 other clams that look fine. He is in with a variety of LPS/SPS/fish that all look fine. The only thing I can come up with is that I had a new sea urchin die about 6 inches from him yesterday/today. Is he gone? Is he doomed? Man, I am so depressed about this. Checking parameters now...