I had a featherduster like the one in your second pic.
The wierdest thing happened...
I woke up one morning and the tube was covered in this white (elmers-glue looking) mucous and the worm wouldnt come out. Over the next several days, every morning Id chck out the tube and it would have more and more of that white stuff. the hermits were even trying to eat it.
Then all the sudden on like the 4th day of mucous-ness the tube was found on the other side of the tank- completely uprooted, and no mucous on it. I picked up the tube and it was hollow with a big hole out of the side.
Im not sure what the heck went on! I havent seen the worm, dont know if he kicked the bucket or is rebuilding somewhere else. Maybe he was trying to reproduce? It didnt look like the tube was rotting, it looked deliberately 'encased' in that white stuff.
I have other dusters healthy as can be, and even a scallop, so I dont think he starved. But, I miss him b/c he was pretty.. JUST like the one in pic#2 you have
I hadnt ever seen another one like him until yours.