What is this white thing?

[moorea]

Hi
Can anyone tell me what this is?
My tank has been running empty for about 4 months and used to have wild caught Florida fish and hermits.
I have never done any reefkeeping.
What is it?
Thanks a lot
Patrick

 

[beth]

It is not a disease. Is it spongy?
Moving your thread over to the Reef Forum.

 

[moorea]

Hi
I don't know if it is spongy, i haven't touched it or messed with it. It is like some kind of tree with branches as you can see on the not so clear pic.It is all white in the center but is all surrounded by a clear film.
It moves slightly with the current.There are a lot more but they are smaller on the dead coral and on the bottom crushed coral too.
They seem to thrive away from the filter current since there is only one in the right side (Filter outflow) of the tank for around 20 in the left side.
I hope someone can tell me what it is. I can send clearer pics probably.
Thanks
Patrick