I've tried multiple Achilles...3-6... before in my 600 gal. It seems to be fine at first but slowly aggression increased and after a couple of month...only one left standing haha
I just added a Achille hybrid in last month...lot of aggression from the Achille at first so I separated them and re-introduced the Achille after one week. That seemed to calm him down.
I had 3 of them before with 2 blue tangs and 2 yellow tang and six flame angel in a 180g with no problems the only problem was hi NO3s ��