a note about the transition, it's one of the cooler things i've been privy to see in this hobby.
we got a trio of females and a male. unfortunately the male died shortly after being placed in to QT (it was sad, he came out sideways, hit the bottom, and that was about it).
so i ran the other 3 through my normal TTM regimen, once they were through and in the grow out system i purchased another male, ran him through TTM, and then in to grow out with the others.
the window of time the trio was without a male was maybe 3 weeks. maybe.
i held them in my grow out system for about 5 weeks, making sure everything was fine, then moved them to the big tank.
about two weeks after moving them to the DT, i noticed the alpha female was starting to change slightly in color, and develop a dorsal spike.
s/he has continued the progression, developing the fin spots, coloration, and markings of the male. while my existing male appears to have actually become less vibrant in his coloration.
so far everyone still seems to be getting along well. the tank is a 155 oceanic, so there's quite a lot of room for 4 anthias, but i was surprised at how fast and dramatic the change was. very cool thing to be able to witness a few inches from my face. unfortunately i wasn't able to get any good pictures of the transformation because of the constant motion the fish always seem to be in.
good luck with your trio, they're awesome fish!