Unfortunately nems move at their own will and you can't really put them where YOU want, they kinda go where they get what they are looking for whether it be light, flow or whatever. Is he really attached to that rock? A slight nudge might make him rethink his position but you def don't wanna forcefully move him or you risk damaging him.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.