Well, honestly, I don't know why all of a sudden they decided to eat the worms. I'd had the coral and shrimp for months. I noticed after a while not as many worms were coming out. Then noticed the tubes were empty. I had no idea why they died til I was watching the tank one day and watched the cleaner pestering a blue worm. Still didn't think much of it since the cleaners pretty much harass everyone in the tank, til I watched him pull the worm from the tube. Again, I don't know if maybe it sensed the worm was checking out or not but, my porites no longer has worms in it.