Not sure exactly what featherduster you have, but survival without tube is very very possible. The lad at the store is wrong,
IMHO. A feather duster is a worm in a tube, when things go bad and a worm leaves said tube, it is trying to survive, not to die. The worm cannot travel with the tube, but is capable of building a new tube. The tube was not a refuge found, but was built by secretion of mucus to bind surrounding materials. Best answer is to leave worm alone. It is out of your hands and more time than not, it will survive and build new tube if given good water qualities/conditions and not harrassed.
