the tube shape and operculum/opercular peduncle (the "stalk" of the operculum) can theoretically tell us quite a bit, but I'm not familiar enough with Serpulid taxonomy yet for it to be of much use at the moment I'm afraid (with ~95 recognized genera in the family, it's a lot to learn about, and I currently only know useful info for about 5 specific genera). The body shape, eyes, specific body parts and certain chaetae (at the microscopic level) are all also used in the identification of specific species, and most of these aren't visible without removing the worm from the tube.
OP, if you want to try for an ID, you'd need super clear pics of the feather crown, the operculum and opercular peduncle, any eyes you can find, and any pics of the worm's body you can get (removing it from the tube would be stressful, so I wouldn't suggest it). Showing the shape of the crown and operculum would be important. This info may at least be able to get us down to a subfamily/tribe level, but there's no guarantee.