Black algae??? Need help!

[Goldie-Maree]

I bought this live rock from lfs he said it was black algae and that my snails and crabs will clean it up. They won't go near it. I've yet to see a picture anywhere on the internet that looks like this stuff. I can't try to eliminate this stuff if I don't know what it is. It feels like rubber and does not easily come off. I had to use pocket knife to scrape a tad bit off to inspect it.

 

[chefjpaul]

Sponge

 

[JFrar]

I swear i've had something similar grow on my reef rocks but not nearly that much...but i did not mess with it and it isnt around any more so i dont know...im kinda tagging along to hear others

 

[Wh00pS32]

Try googling liver sponge and see if it's the same.

 

[Goldie-Maree]

Try googling liver sponge and see if it's the same.

It looks just like the google images of black liver sponge not much info out there on it. Will it eventually cover this rock.

 

[Wh00pS32]

It's really unpredictable but can become a real pest for some while others don't seem to have too much trouble with it. The biggest problem is that it's virtually indestructable, i've heard of reefers here in the uk that have dried rock out for months and it's still come back, others have closed tanks down because it has been so invasive.
But there are also people that have had it in thier tanks without it becoming a problem.
I honestly don't know how to advise you as it's such strange stuff.

 

[WetWhistle]

It looks like a sponge to me. they are harmless filter feeders. I have never had an negative issue with a sponge over the years. Most bloom and are gone just as quickly. I myself would leave it be as sponges have great effect on water quality and help filter it. Some even have a symbiotic bacteria that grow in them that uses up phosphates.

 

[evolved]

It's a sponge. It it's threatening to overgrow a coral, you can scrape it away from the rock.