About a year or so ago I found a large bristle worm had come into my main tank when I added a large piece of live rock. He was about 10" long and about as thick as a pinky. I was told that he was harmless and would feed on detritus, so I never tried to remove him. I used to see him every 1-2 weeks, but I have not seen him in about 3 months. Is he dead? I have not seen any spikes in Ammonia or Nitrite, but the Nitrate level has been a little higher than normal for a while, so I have been doing larger water changes. I think I know where he hid out under a large rock. I think I should do nothing but isthere any reason I should try to find him?