Can someone id this please

[jstrong]

hi, this has been growing on my mothers live rock for about 6 months now. does anyone know what it is. And could you let me know if its bad. thanks

 

[granny]

It appears to be sponge-which is only bad if it dies off! It is another intersting item that just grows from nowhere on our rocks-or we can buy it!!
The upright thing is the siphon-for intake and expelling water/nutrients.
Is that really the color? I have lots of sponge in my tank, but it is either gray or orange.

 

[jstrong]

thanks for responding so quick. yes, thats the actual color (a mint green). thanks again

 

[mikeyjer]

I have the same color in mine!!! :happyfish