I had a group of about 8 in my system at one point in time (of this species, supposedly one of the easiest to keep of the Anthias). Keep in mind that these fish do not live all that long compared to many other fish we might keep (angels, clowns, gobies, damsels, etc.). My experience was that the male rushed around very fast trying to keep all the females in line (tough job for any species I suppose!).
This resulted in the male dying fairly early and then the next biggest female taking over the job (becoming male, as those that know about Anthias will understand). The process continued until there were no fish left. I don't remember exactly how long it was, but I'd say probably more than 1 year, but less than 3. I probably have the exact notes somewhere.