whats going on?

[burtone]

i have this white coarse spongey stuff growing aroung and invading my zoo(dont know the name, kind of yellow and feathery) thos stoff statred in a little spot and has spread to the entire rock, ir dsont scrape off eaisly and just come back, any ideas???????

 

[Chemguy85]

umm not really sure but a clear picture of it would probably help a lot

 

[ept04]

I think I have seen something like what you are describing on some zoa pictures online.....I'm curious too