A Black Ghost Knife I think is awesome, and if the goal is a 200 maybe a pair of Oscars... (grow them out and then move them over)
edit: just saw you didn't like Oscars
You need a 125 gallon for a pair of Oscars. So you could fit more than a pair of Oscars in a 200 gallon. Just pointing that out.
Both pairs would kill each other without a dividermidas and black belt pair