I'm not sure if the ricordea will kill it or not, but they both seem to be fully opened. If you want it to colonize faster, I'd definitely frag the zoa off the disk or whatever the ric is on, and attach it to something else. Since it's just one polyp, it shouldn't be hard to peel it up by it's foot, or break off the piece of the frag disk it's on. Those disks crumble really easily.