I have had these two green chromis for over two weeks now and they are still scared like hell when I come to the room. When I first got them, they adopted a corner of the tank and would just stick there. Give them time. As for feeding, I just give them a little bit of flake food, twice a day. I tried once giving them bits of shrimps, but they did not ate them. As quarryshark says, they have been through a lot, they just need time to adjust and feel secure in their new environment.