Hi Matt
you might try John Delbeek, he supplied a culture of arcatia for Frank Baensch. Also perhaps Frank can chip in with a source.
There is a guy in the UK,
claytonjohnsmith@hotmail.com, he does sell cultures. In your search you might also check out Euterpina acutifrons, it was also used and cultured in Hawaii. I think both are good candidates for centropyge culture.
Many of these people isolated their arcatia out of collections, if you want to go that route you can try Sachs Aquaculture, Paul does have fresh collections, I have considerd getting one and seeing what emerges as the dominant one over a period of time.
Reed mariculture does sell a phyto that works with calanoid cops.
Most labs use nanno but its not the best for calanoids. Altho nanno is used.
Luis is right on, some of us should be keeping some cultures going for these. The problem is it takes a LOT to produce many, figuring if you start with ~ 2000 pods in a new culture its about a month to get them up to ~ 60,000. In that time you'll get 100 times that many rots. So, most of the culture suppliers stay with the bigger benthic pods that also produce faster.
I'm going to be searching and will share what I can find, you've been generous with what you have been discovering. If you find some sources post here, I'll do likewise.
Luis, got any ideas where ?
My defense, I wasnt in the desert while you were preaching, well, alright, I was for part of it but there wasnt any 'net connections there.