HELP What is this? Pic Posted

[SoulFish]

What is this white area I just noticed it tonight, and it's fairly recent? Is that piece dying? I've recently lost a couple pieces to weird things they just turn into jelly and disintigrate but like in 2 days, Whats going on how do I treat it?

 

[seminolecpa]

Check for monti nudis at night with a flashlight. Doesn't look like their handywork but could be.

 

[Euphyllia]

That stuff grew on a rock in my 14g. I think it might be some sort of coralline algae. I'm not exactly sure, but just guessing.

 

[Knucklehead]

looks like a sponge to me, or its just because of no light is hitting that spot of your coral.

 

[Euphyllia]

Now that you mention sponge, I have a sponge in my 34g that looks more like that than the algae I said it might be does.