Your reef will need to feed it until it gets going. They will eat mysis eventually. Do you have enough pods and other microfauna for 2 of them? Even the ones that eat aiptaisa take a while to get going... and then they won't work that hard to get any down in cracks, or in heavy flow, or if they just don't feel like it. ...and the aiptasia come back once you get rid of them. Some don't ever eat any.