Yellow substance growing

[Lynnds6]

Can anyone help me figure out what this yellow stuff is growing on my live rock?

 

[Alexreefer]

I think it is a sponge. If so then good guys but just to double check lets have some more people help us.

 

[Saveafish]

Sponge bob he is good

 

[Lovemyreef2015]

Looks like sponge to me

 

[Rjukan]

+1 on sponge, and that's some really nice looking live rock. Where did you get it?

 

[Mastiffsrule]

Sounds about right

 

[Lynnds6]

+1 on sponge, and that's some really nice looking live rock. Where did you get it?

I actually bought it a year ago with the tank and have added montipora,ect to the tank