I just went and looked at my friends tank that he has had for a little under a year. Anyways a few weeks back he noticed worms in his tank. They stay under the rocks and hardly ever come out. They're dark on each end and kind of a pinkish red in the center of their body. They look kinda hairy to. Anyways he wanted me so see if you guys might know what these are and if their good or bad for his tank. He noticed one at first and today when he lifted up the rock that they stay under and he noticed 5 more. The biggest is about an inch long with the others being about a half inch long.