Strange bright yellow growth

[Holygral]

found this towards the back top of my set-up. Someone suggested that it is some kind of sponge. But cant find anything that looks close. Thanks


IMG_2261.jpg photo by Holygral | Photobucket

 

[sanderson417]

I have similar growth on my rocks, but mine is white. Mine is definitely a sponge.

 

[NarwhalLover3]

Google "Yellow Encrusting Sponge"