Killer Sponges? (pics)

I'm a bit worried about a frag of zoas in my tank. They havn't opened for a couple of days and the only noticable difference is that a sponge has begun to overtake the frag.

I was kinda under the impression that zoas could take a sponge (mainly because the frag next to it has 4-5 zoas that are nearly drowning in a different type of sponge yet still open daily).

So I did a FW dip just before heading to work tonight (let ya know how it goes).
Just a few pods suffered as a result; no nudis or worms.

I was just wondering if anyone has heard/seen of this type of situation before.
I'm really worried because this sponge type grows everywhere there is shade in my tank.

Here's a pic with a tube of the sponge indicated. Also are a couple of pics of the type of sponge I'm talking about.

I find white sponge bothersome. I always remove it when it approaches the corals because I am afraid of problems like this. I would like to know if it is killing them off though.

Yeah it looks like the sponge was the problem after all. I noticed it was annoying a mushroom as well.