Black Spongie Stuff

[pixiefish]

I've noticed in some of my live rock this black rubbery looking stuff. I was able to pick some out and it felt spongie. What is it? Is it a type of sponge or something else?

 

[pixiefish]

Bump

 

[arlene1995]

Couple things here: How old is your tank and is the black stuff porous in appearance?

 

[jigga w00t]

I have that stuff too, it came into my tank as a hitchiker. I wish it was not in my tank, though. The only lfs owner I trust told me "its not bad, but its not good" I don't know what it produces, but every couple of days the sponge has bubbles on it. I think cyanobacteria produces nitrogen bubbles, the sponge might do a similar thing.
Does your spongie stuff have bubbles on it? If so, we might have the same stuff. I searched threads on this site, but there aren't really any helpful ones...

 

[deejeff442]

i have a big rock with it on it for a couple years now ,i think it looks cool only black thing in there.
it has not spread to other rocks and gives the tank another color.
it doesnt have bubbles on it.