Carpets can eat fish... so be aware.
All anemones can move. So, if you consider your other animals dear, an anemone might not be a good addition. If you are willing to lose an animal, coral or two/five/ten... then you might consider one.
I've kept a multitude of other animals with them. It isn't about what you have now, but about what you'll have in the end. A long while back I think I lost 3 baby banggai to my carpet, but didn't actually *see* it happen. I realized that adding fish was a gamble at that point.
-A