Clowns tend to have tend to have Jekyll and Hyde personalities. They are known to be quite aggressive and they do get big. The previous sentence can be used with the queen trigger also.
Nigers get big but tend to be a more docile trigger, that some consider reef-safe to a certain extent.
Never had a Blue Line, so I can not comment on that.
I cannot remember... .are the dragon morays in the same expensive grouping as Hawiaan Dragon Morays?