I think the bi color is a swimmer type fish so if so, he should be ok. The scooter shouldnt bother it and the watchman may do the open mouth thing of aggression but it's just their way it seems. lol at least from my experience.
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.