that rock can be soaked in high salinity stuff too. barelycuda did this for bristle worms and he had good results, the high salinity is intolerable for worms and the bacteria can deal with it.
oh and by the way. just to throw this out for kicks and giggles. and no insult is intended. you have just proven why anarchism is unsustainable and government must be inserted:
if you just left the tank as it is that would be like anarchism: free for all, no government (as in the tank keeper). but this is bad, there is an poor balance, and fish are dying (like people would be starving etc). so the best solution? install government restrictions, as you have said. the government restriction would be to eliminate the problem(get rid of all the fire worms).
once again this is just my idea of being silly. i have no intention of angering you, or downplaying your convictions.