"Is it normal for some of the polyp's to be retracted? "
Well, yes and no. Zoas and palys can be very temperamental at times. Often we think we have a predator or hoist within the colony and we run to prepare a dip. Not always the case nor the proper response, here's why. Polyps will periodically retract for several days to sometimes 2 weeks, it's true. It is a means they use to clean themselves externally and it is perfectly normal. I have a couple colonies in my tank, like clockwork, will retract for a few days every couple of months. It recently happened for the first time with one of my favorite zoanthid colonies. My buddy told me that they needed to be dipped quickly, I told him, "not so fast". I knew that I hadn't added anything new in well over a month, if there was a predator, it would have manifested itself already, so it wasn't a predator. As a matter of fact, I hadn't added any new, fish, inverts, corals etc. I saw no signs of BI or fungus, leaving me with the simple deduction that they were simply cleaning themselves. Sure enough, 12 days later, they sprung back open.
If you have some retraction here and there or periodically, the reasons could be as I stated above, or, a simple group of pods could have irritated them enough to close for a few minutes, this is also very normal. Small snails or small crabs crawling by or around the polyps will cause them to retract, a blast of current or even excessive lighting can cause retraction. A parameter that is way off will cause retraction, there are literally numerous reason why. The key is daily observation and getting to know how certain colonies react and keep a log of which ones and how often they retract. This can greatly aid you with potentially unnecessary dipping.
I'm sure I have confused you by now, LOL, but small periodic retractions for a very short term are normal, if it goes beyond a couple of days and you just want to play it safe, remove the colony along with a gallon of tank water. Invert the colony face down in the tank water outside of your tank in preferably a white bucket and swoosh it back and forth in a clockwise to counter clockwise twist for 30 seconds, then place it back in its original place. The white bucket will highlight possible hoist or predators which may have been the culprits. Always run your actinics only when you have remove a colony for any reason, surgery, treatment, dipping, salt water swoosh etc.
BTW, forgot to add this, persistent retraction isn't normal.
If you always have colonies or polyps retracted, this is not normal.
The best thing to do is pose the concern here in this forum along with as much detailed information as possible, detailed description, coloration, pinching, detaching etc, and someone in this forum will be sure to help you. Post every parameter you can which will also help.
Here's a link that might be of some future assistance to you.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1154238
Keep us posted and I hope this helps.
Mucho Reef
