Has anyone had a intact (worm w/ attached crown) worm leave its tube? I wouldn't think a healthy feather duster would leave its tube and expose its tender body to possible predators. My feather duster will still retact its body w/ crown back into the tube, but then it comes back out again exposing its body. I think its dying...its never been quick about pulling it crown back into its tube....more like slow motion. The only thing new I have added to the tank is 2 peppermint shrimp. Would small shrimp attack a large feather duster?