Black slime growing from Caulastrea?

[Dan13]

Hey guys, can someone take a look at these pictures and see if you can tell me what the black/purple stuff is?!

It has been growing out of my Caulastrea since I got it and us on my rock. It seems harmless, I just want to make sure!

 

[Retro Reefer]

Looks like sponge.. that’s a nice and healthy looking Caulastrea you have.

 

[Dan13]

Thanks Haha. So I should not be worried about it then? It just looks and feels weird. It's like a thick gel or something. So hard to explain what it is like!

 

[timrocks311]

yeah, looks like a sponge, which is a good thing. Just watch it doesn't overtake the coral.