Are we talking about Black Oscellaris?
If so, their natural hosts in the wild are Ritteri or a few species of Carpet anemones - all of which have a very poor survival rate in captivity.
IMO a captive propagated BTA is the most responsible choice for a host anemone in our tanks, and also probably the hardiest. Problem is, it's not a natural host for Oscellaris (it is for Clarkiis and Maroons, however), although Oscellaris have been known to take to them in captivity.
Another option to consider is surrogate hosts (hairy mushrooms, etc.). Joyce Wilkerson's book on clownfish is a great resource for this type of info if you want to learn more...
HTH