Can someone tell me what this is?

[kdpuffer]

So I have these tubes on my live rock. I did some google searching before and came to the conclusion they are sponges but recently I have noticed what looks like feeder tentacles coming out of them. You can actually see them in the picture. I have three of these things all in a little cluster, they have quadrupled in size and seem to go to sleep (shrink and go flaccid) after daylights go out. Any help would be great.

 

[Flreefer]

Not sure KD, but just wanted to say, that's one kick &$@ lookin zoo!

 

[kdpuffer]

Thanks dude

 

[Kickingfish]

Looks like a species of tunicates.

 

[Rutrag]

They look somewhat like something I have called snake zoas or snake polyps. Mine extend their tentacles at night, and have a little bit of green fluorescence to them. Here are mine:

This pic is from shortly after I got them. They are more yellowish in color now.

 

[kdpuffer]

They look somewhat like something I have called snake zoas or snake polyps. Mine extend their tentacles at night, and have a little bit of green fluorescence to them. Here are mine:

This pic is from shortly after I got them. They are more yellowish in color now.

I googled them and they look very similar, mine are very smooth to the point they are shiny.