That depends. I've had some that take off right away and add polyps like it was a weed. Then I've had some that take their time and slowly put on polyps. Most zoas I have needed a break in period of a few months to start showing faster growth. Frags seem to take less time to take off (since they've been in my system for longer), but it is still hit or miss. Then when you get into the different types of 'zaos', the whole world changes. I've had a small frag of PPE (Protopalythoa sp.) for almost a year now that has only added 4 polyps the whole time, while some have much faster growth rates than that on the same coral...