I bought my first clam and I am not sure if he is doing as well as he should. He was opening up good for the first few days and now a week later he is barely coming out. I do not think any fish are nipping at him and wter quality is optimal. I have two 175W 15000K's and two VHO's one actinic blue and one 50/50. He has been on the sand at the bottom of the aquarium. All my other corals look great but they are mostly sof corals. Any thoughts.