need some help identifying a creature in my live rock and some other misc questions

[Duckieluck]

So I've had my tank for a while and near my zoa there is a pom pom looking creature and from that same spot it looks like a white/ translucent arms come streatching across the whole entire rock the zoa is attached to. At first I thought it was some algae but it reacts to the lights being on and retracts it's long arms back into the rock.
Here is the best picture I could get.
The white pom pom is near the left of the bottom most zoa. The leg of the long tentacle creature is near the right of the bottom zoa.

http://i.imgur.com/rkFGBpV.jpg

Another question I have is to ask if my squamosa clam is gaping I just got it yesterday and I'm not sure if the mouth is where it's supposed to be or if the mouth is gaping due to stress.

http://i.imgur.com/ABBCaBX.jpg

Thank you all for your help, you're all so knowledgeable and helpful the last time I posted you let me know how to aquascape my tank better.

http://i.imgur.com/UBvlHj1.jpg

 

[BrianOD68]

the white "pom pom looking creature" looks like a feather duster to me. I have them scattered around my live rock. I have heard mixed reviews on them. Sometimes they can get to infestation stage. If it's just a few I don't see an issue. Just my humble opinion but my no means am I a veteran with the reef scene.

 

[stingythingy45]

Looks like a hydroid to me.
http://www.marinelifephotography.com/marine/cnidaria/halecium.htm

 

[this is me]

Doesn'nt look like a feather duster to me either. Feather duster is good to have. And usually never a problem.
I'm also thinking its some kind of hydroid in which case you have to kill it immediately. Joe juice, kalk paste, or even epoxy or super glue will work.

The clam looks fine. Just need to tip it a little so that its not resting on its side.

 

[cilyjr]

I thought hydroid as well. Also think clam is ok