By fireworm do you mean the Hermodice sp.? Just making sure because some people use the term bristleworm and fireworm interchangeably. Ordinary ole bristleworms come in all sorts of colors like blue and indeed red. I have the prettiest red ones in one of my tanks. But actual "fireworms" are very uncommon to find as a hitch hiker in thehome aquarium.
LOL, we were posting at the same time David.