Yellow slime on rock - Is it a sponge?

[Scubafrog]

My wife picked out this rock when I set up my tank a few weeks ago because she liked the yellow next to the purple rock. I liked it at first but then my curiosity kicked in and I became interested in what is actually on the rock.

Is it a sponge or something I should be concerned with? The LFS sold it to me so I assumed it was okay. Just newbie paranoia.

Thanks!

 

[fishroomlady]

looks like sponge to me

 

[Pfisherman]

That is nice sponge growth.

 

[Scubafrog]

So it is a good thing? I also got a nice, but small, brittle star on the same rock that is starting to come out more. One rock had some star polyps that are starting to grow. The only thing I have been scared about is the amount of bristle worms I have seen.

Definitely an interesting hobby.

 

[fishroomlady]

it really is an interesting hobby sponges are filter feeders and may slowly disappear or will stay hard to say. They are a good thing

 

[jp415]

I have this issue on my rocks. Would this be something I need to be worried about?

 

[Rmckoy]

I have the same sponge but typically mine started growing on the under side and dark side of the rocks .
on top exposed to light will eventually die off .