spaggetti worms

Found a red slimy worm that has stringy extensions could be a spaghetti worm but never seen one red. Sifted through the sand to see if there was more and didn’t see any so far. This one found going after my torch.

Is my pulsing Xenia complete dead or does it have any chance of recovering. If the cause of Xenia’s death Was possibly death by was being colonized and eaten by some kind spaghetti worms and bristle worms? The bristle worm was entirely red a little less than 6inches which is why I’m afraid that...