Zoanthids... Do they retract on a regular basis?

[zmazza]

I have a colony of zooanthid polyps that have almost doubled in 3 weeks. They are doing extremely well. While moving them around to do some tank maintenance, after putting them back into their same spot, I noticed some of them weren't opening. I figured this was because they we're stressed out from being moved. I saw that a lot of them had opened up within a few hours, however some remained closed.

They are open today, though, but periodically, they will close back up.

Are they like normal anemones? Will they expand and contract? I know that corals are esentially from the anemone family, right?

Please help!

[Hellspawn]

My zoos close up every time the light gets turned off at night and open again when the lights go on. They also close if they are physically disturbed :)

[Paintbug]

they will often close one at a time. something may have bumped one, or it may have caught something to eat, etc. normal.

[zmazza]

I didn't think about it closing up to eat. Great replies though, thanks for helping clear that up.