Any ideas what this is?

[fftfk]

I have two Zoa colonies I haven't been having good luck with. I have tried different spots in my tank but both are slowly receding.

As my other corals are doing fine my lfs suggested I might have a parasite and do a two minute fresh water dip. I did this weekend and then noticed these two white snot looking bulbs on them tonight.

Any idea what the white stuff might be?

 

[ps3]

look like sponge

 

[650-IS350]

sponge, some are ok, some are invasive and grow/suffocate your Z's and P's, I've usually just used tweezers to rip them off.