I thought my Orchid Dottyback was a model citizen until I introduced a Helfrichi Firefish after it and it was constantly chasing it for the first couple days. Now the Firefish stays in hiding except at feeding.
The Orchid never bothers the Tail-spot Blenny in the tank before it. It's a great fish and very peaceful for a Dottyback, but I would add it after all the smaller, more timid fish.