I am not a nem guy, but i have read a great deal on them, and in my opinion, the general consensus is to let them do their thing. Once it is comfortable, then start moving the rock around if you can without harming anything. But sometimes it just needs to get used to the new lights, flow, etc... If it is in a place that may be an imminent threat to it's health, then moving the rock is a good option.
but i am not a nem guy.
good luck