What are your water parameters? Usually fish going to the top indicate ammonia or some breathing issue.
When I got my watchman last week the first few days he was swimming at the top of the water, really worried me, but after a couple days he has settled back down to the substrate in a burrow.
Fish sometimes change color under stress as well, are there any fish that could be picking on 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.