I had a single polyp turn into 13 rather quickly. All of a sudden they closed up, never opened again, and slowly melted away. The rest of my zoas were just fine, and other local guys complained of the same problem.
Not sure this is long term but I traded for some almost 2 years ago. They multiplied to around 40 from 5-6 I started with. They are very pretty and now have a rock anemone living right in the middle of the colony.