Guys, keep in mind this thread is almost 5 years old

That worm was in my tank in another state and is long dead.
That said.. it was just a common fireworm, I never got an exact species name for it, but it was not a predator, wasn't one of the other 'dangerous' varieties for the tank. It was simply a very large scavenger, a very large and cool critter.
I never noticed any of that behavior at all. It simply came out when I fed the tank or picked over the remains of a dead fish when that happened. It co-existed a couple of years with small and large fish alike, along with a number of other animals.
FWIW.. fireworms are found all over the world, not just the Gulf. They have them in Hawaii, in the western Atlantic and various other places as well. Specific species are regional, but the family itself is not. This came in on Fiji rock originally, though its possible it was transplanted from some other rock since the supplier I purchased from also had Marshall Island and various Tongan varieties that they sold.
Here is a Haiwiian variation
Hawaii Fire Worm
Here is an Atlantic variety... Homodice which IS a predator.. the colors are similar but the body is distinctly different.
Atlantic Variety