What other species are in your tank? There's a good chance that animals specific to areas like the Red Sea or the Indo-Pacific region will have developed almost no natural defenses against an Atlantic anemone.
We had a Condylactis anemone for about 26 hours once. After acclimating (which went quickly, these anemones are quite hardy!) it proceeded to wander around the tank, which I figured was normal since most anemones prefer to choose their own spot in the tank. A few hours later it had wrapped itself around a small leather
frag! BAD ANEMONE!! (put on the rubber gloves, move the anemone back to original position, feed it a few krill after placing it to con it into staying put).
Woke up in the morning and it was on the other side of the tank, upside down... because it's mouth was around a tiny caulastrea
frag! (put on gloves, put anemone back in the fish bag, went back to the
LFS).
That was the first (and last!) time we introduced an aggressive Atlantic species into a tank that's almost 100% Indo-Pacific specimens... Lesson learned! (and the 2
frags have mostly recovered).
PS. here's a mugshot of the culprit:
Anemone (Condylactis gigantea) on Flickr - Photo Sharing!