I don't know if a carpet is the best idea with any creatures. My best friend had a carpet and it measured 21 inches fully extended. It was about 3 years old and we use to see stuff come up missing all the time. The only thing that we didn't fear of loosing was the clown that was hosting with it.
lol
My thought with carpets is that no matter how good you keep them fed they are still carpets and carpets are very aggressive for anemones in my opinion.