Strange Creature ID?   9/14/13
Hello all,
<... six and a half megs of pix. What are our requirements?>
I have a strange creature that I would like some help identifying. There are many of them (over 50 that I can guess) in my 29 gallon BioCube reef.
It is semi-transparent to opaque-white worm like creature. They are slender (~1/32"-1/64" diameter when stretched) and long (1-3" long) when fully extended. It seems as though there are adult versions and newer smaller versions. They are fixed on a hard surface at their base end and they don't travel from those fixed points. They are found on my live rocks as well as in between my Zoas and Green Star Polyps. They have fuzzy or furry looking appendages all over their length. Their 'head' is almost Q-tip shaped when fully extended.  They extend in the flow of the currents but can somewhat control their direction of movement if the flow is slow enough. However, they are only extended in low light or at night. They will retract and withdraw back into their 'base' in 3 or 4 jerky movements within a second or two when a flash light is pointed at them. During the day, they are nowhere to be seen except for the ones attached in dark shaded areas only. At first, they don't seem to affect anything. They don't affect my soft corals (Hammer, Frogspawn, Duncan, Leathers, Ricordeas etc. However, I started to notice that some areas of some of my hard corals (Acroporas) were 'bleaching'. After the 'bleaching', that area began to die off and turn to base skeleton. Upon further examination at night, I noticed that these unidentified worm-like creatures were constantly touching the corals on and off. Those areas that were being touched were bleaching and dying off. I then scraped the base where a few of these worms (near the Acroporas) where extending from to try and remove them and noticed that for the next few nights the worm-like thing was no longer there and within a few weeks the coral began to heal and regrow in that area.
Taking pictures at night was very difficult and I couldn't get anything worth sending as they are so thin and almost transparent looking as well as constantly moving in the current. However, I removed a Zoa plug that happened to have one of these 'creatures' and dipped it in Coral Revive for a few minutes. The Coral Revive appears to kill the 'creature' so I scraped it of the frag plug and was able to take a picture of it. For reference sake, the base of the black container is ~2" across.
Any help with ID'ing this would be greatly appreciated. Thanking you in advance.
Regards,
Nick
<Mmm, my best guess is that these are Pennatulaceans. Bob Fenner>

Re Strange Creature ID?    9/15/13
Lynn, what do you think? Pennatulacean? B
Re: Strange Creature ID?    9/15/13
Lynn, what do you think? Pennatulacean? B
<That would be my guess as well.  Here's a link with some examples for
Nick: 
http://www.accessscience.com/loadBinary.aspx?filename=496200FG0030.gif   
Take . Take care,  Lynn>
<<Thank you Lynn. B>>
Re: Strange Creature ID?    9/15/13
Hello Bob,
I sincerely apologize for the previous large sized attachments... I had no idea that they were over 6 megs.
I've attached 2 much smaller sized pics for you to view.
My other questions that I forgot to ask are:
a) are they as harmful as I think? and if so
b) is there any way to remove them other than by physical means? I notice that none of my clean up crew or shrimp touches them.
<Likely not very harmful, though are Cnidarians... and very likely will just "go"; pass on their own. I would not make extraordinary action to eliminate nor remove them>
Thank you for taking the time to view the pics and answer my questions.
Regards
Nick
<Ah, welcome. BobF>

Re: Strange Creature ID? Penn...    9/16/13
Thank you very much for your prompt reply! I greatly appreciate all your help.
Have a great day!
Nick
<Ah welcome. You as well Nick. B>