Until I pulled my tank down recently, I had 2 large feather dusters in my tank. One of them was perpetually happy, never did anything out of the ordinary, but the other was a different story. On one occasion I noticed that it threw it's crown, and the next day it had crawled out of it's tube completely and was curled up under a piece of rock about 6" from it's tube. I figured "what can I do?" so I left it to do what it would... About a week later I looked in the tank and voila, it had crawled back into it's tube and had regrown about a cm of crown and was out and feeding. I believe it tossed it's crown 2 or 3 more times in the time that I had it and always within a week it had regrown enough to feed with.
Very interesting critters!
