Is there are rule of thumb for the number of bristle worms? I'm new to the marine world and got a used tank that came with rock that sat out of the water for some time. After setting up the tank and letting it run for a while, I noticed the worms. I added a piece of shrimp one day, and dozens and dozens of them quickly emerged and attacked it. I was pretty alarmed at the site and my first instinct was to get rid of them. I read more about their beneficial effects and decided to try to keep them. Now I wonder how many I should have. So far I'm going on the advice that if there isn't enough for them to eat they will naturally die off to a level the tank can sustain. Are there dangers in having too many? So far everything seems very happy.