I just got a Maxima Clam and have it in my tank on a little piece of live rock. It keeps on falling off and even seems to be moving around a little bit. I wasnt sure if I could just put the clam on the sand bed and it would anchor itself there? or do I need to put it on a piece of rock and wait for it to attach? This is my first claim, and it seems to be doing fine except that it keeps falling over for whatever reason.