Bristleworm on zoanthids?
 

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

If you have live rock then your going to have some worms. Bristle worms shouldnt pose anykind of threat to zoas. I have all kinds of worms in my reef. Bristle worms can pose a threat to sps, but I've never had a problem. What are your perameters? How often are you feeding? More than likely its a water quality issue. Do you have a skimmer? How many watts of light? All of my zoas open under halides.

196 watts t5, 3 daylight, 2 actinic (still experiencing some diatoms so light cycle is a bit short--actinics 9 hours, daylight 7)
Temp 78
S.G. 1.025
Alk--approx 2.8 meq (just ordered better test kit for alk)
PH 8.4
Ammonia 0
Nitrite 0
Nitrate 2.5-10
Have not recently measured Calcium but it has always been at least 450

I am running a corallife 65 skimmer plus 2 HOB filters. The biowheels have been removed and and I change the filters every two weeks. Water is crystal clear. At present there are only 3 smaller fish in the tank. I alternate feeding Formula one pellets and frozen mysis. I feed lighty 1-2 times a day. Also have the usual CUC

They may be just adjusting to your tank. I really don't think that the bristle worm is causing them not to open.

how long have you had the zoas? What kind of flow do they have? Did you get them through the mail, from a store, or from another reefer? how long were they in the packaging for. I got some that were shipped overnight, but were out in the 20 degree weather for half an hour. The temp in the bag was about 62 degrees when I opened them. It took them almost 3 weeks to totally open up, and now they're fine. So, I really wouldn't worry about it too much yet probably.

Bristle worms wont hurt you zoas...they will only clean them...if a zoa is sick or dying the worm will eat it...

and as you kow a Goni in a three month old tank is bad idea...

it sounds like you could be feeding too often...unless they are live foods you are feeding...dead and or frozen, rotifers, phyto and cyclops are going to put a strain on your system..