It looked dead as it seemed to be moving with the water currents. I let it be and would see what it was like the next morning.
Well, today morning this "worm" had moved about 4" to another piece of live rock. I turned on the main lights and then I saw movement from what I thought was the head/tail. Looking closer there was actually a smaller (1" length, body width approx 0.065-0.080") dark worm with a pink head and small spikes down both sides taking bites out of the worm in the above picture. Sorry for no pic camera battery was dead. Came home in the evening, the above worm was gone and I couldn't find the small 1" worm.
Any thoughts on what the small worm and the worm in the picture are?