from what i have seen, dragons are an invert hunter, looking for tasty shrimp and other small creatures to eat, that is why they flip rocks and move sand around. my main concern would be a clam on or near sand might fet buried while the dragon forages for critters.
Thank you. All my clams are in the rockwork. All my rocks are fairly large and most of my corals are pretty securely attached. I'm not worried about shrimps and such because I dont keep any. I have a predetory reef going with a niger triger, fimbriated and red dottyback. Would reallly like to add a dragon wrasse.