Fireworms are a type of bristleworm that is a lil more aggressive but otherwise looks very much the same. Rit was saying that even regular bristleworms that get big enough will take down inverts like shrimp after molts. So when they get that big I think its best to just take it out. The nylon stocking trick works pretty well in my experience at culling the worm population. Just "borrow" a pair from your wife and put a shrimp in it... then tie it to a rock. The worms will get tangled up in it and are unable to extricate themselves.