Black sponge or alge or somethin growing on one of my rocks

[R.Allard]

i bought a piece of live rock from a lfs because it had a nice tubeworm and some featers on it and a little bit of this black mold looking
alge or somethin on it and now the black stuff is covering 25% of the rock .does anyone know anything about this stuff and should i be
concerned???
thanks R.

[Tim Marvin]

I can't remeber the name of it off hand, but it will spread and encrust the whole rock given time. It is easily scrubbed off with a tooth brush and won't come back. It has some whitish look to it also?

[Tim Marvin]

I can't remeber the name of it off hand, but it will spread and encrust the whole rock given time. It is easily scrubbed off with a tooth brush and won't come back. It has some whitish look to it also?

[ratboy]

I have several rocks in my 90 that have cool smooth black sponges growing on them. A few of them are 2"x2" with big siphons. I have also seen what looks like bread mold on the undersides LR that sat on the sand.

[Nano_Steve]

the breadmold stuff erik is talking about i have a bunch of all over my rocks. when i explained that it was black and looked like it had a layer of something resembling the mold found on oranges when they go bad i was told it is black cyano algae and can possibly lead to disease and even death :shock: i have been using the miracle stuff(chemi clean) for about two days now and it is noticeably retrieving. you might want to look into getting some chemi clean(even if it doesnt turn out to be black cyano this stuff works wonders on water quality).

steve

[R.Allard]

hmmm ok!
the stuff im lookin at is all black and smooth almost as if you were to take a black marble and mold it to a rock . if that makes any sence :roll: thanks for the help i think im just going to through the rock out in the back yard and be done with it . its on a small piece of rock .. rhe only thing ill miss is the nice tube worm thats on it and the 4.00 i spent for the
tube worm..
thanks R.