Ah, in that case, these are the fairy wrasses I've had experience from most mellow to least mellow:
- Pintail (c. isosceles)
- lunatus
- lubbocki
- exquisitus (both african and fijian (no red)
They were all low-aggression, but both of the exquisites surprised me a little in that they were noticably more aggressive that the others even as juveniles ... a lot of regular, frequent chasing of other fairies to show and maintain dominance compared to the rest. (BTW - the two exquisites were not held together.)
While I've not had one, it's my understanding Rhomboids can be very mellow as well, much like the pintail.