I am trying to identify this new growth. I'm looking at stringy white branches reaching up from rock. I used a brush to clean off one rock, it seems this one cause a coral to close up it was creeping up coral edge. any help appreciated.
I guess that depends what it is. If sponge like stated above then nothing too alarming. If pest of some sort it may spread.... The worms and hydroids I have had in tank all retracted when touched that's why I asked
This is definitely a sponge. You can pull it off with a tweezer. They are good filter feeders for your tank; however, don't let it get out of control as it can sufficate your corals. You might have high nutrient level in your tank, which aide these white sponges's growth. AND DO NOT BRUSH IT OFF... as they spread easily. PULL IT OFF WITH A TWEEZER. Check your Nitrate level.