Bristleworm on zoanthids?

[otrlynn]

When I put some cyclopeeze, zooplankton, and phytoplankton in the tank via turkey baster a few minutes ago (mostly to feed a goniopora that I bought in a moment of newbie ignorance), I noticed a small worm come out on one of my zoa rocks. I tried to grab it with tweezers for a closer look but it disappeared into the rock. I have never seen any kind of worms in my tank ( a 58 which has been set up for approx 3 months, but with rocks and water that came from an older tank). I looked up a picture of a bristleworm, and that is a possible ID. These zoas have never been totally happy except when I first bought them. I have T5s and I have tried the zoas at all levels of the tank and can't get more than about 80% of the polyps open at one time. Would the zoas be unhappy with the bristleworm, or is there a more likely hitch hiker with a similar appearance? Suggestions appreciated. I think it is unlikely that I can get a photo. Thanks