I just replaced a disappearing firefish with a lawnmower blenny. About a week after I added the blenny my Squamosa clam & all mushrooms closed up tightly. The clam will open slightly when the lights are on but it definately does not look normal. It's a 20gal reef tank that has been up and running for about 2 years with all inhabitants living healthy. The only recent change was the blenny addition after my firefish disappeared. All tank parameters have been within spec for the past 2 years. My calcium was slightly low after I added the clam but I upped the dosage of my calcium supplementation & now it's fine. I also have a hammer coral, pagoda, leather, candycane, zoos & gonopora which are all fine. It's just the clam & mushrooms that are a problem. I haven't seen the blenny picking at anything. Do you think he's bothering the clam & mushrooms and I just haven't seen it? Any advice would be appreciated. (I also did two 5gal water changes over the first week after I noticed a problem)