What are those: friends or foes?

[Oropher]

Hi folks,

While i was breaking live rocks for rescaping, I stumbled upon these black haired things inside a live rock.



1. Does anyone know what those are?
2. Are those friends or foes?

Thanks folks.

Happy reefing.

 

[living_tribunal]

Hi folks,

While i was breaking live rocks for rescaping, I stumbled upon these black haired things inside a live rock.



1. Does anyone know what those are?
2. Are those friends or foes?

Thanks folks.

Happy reefing.

Has uh, Venom been playing around in your tank?

 

[Oropher]

I'll try to notify Spiderman then

 

[living_tribunal]

I'll try to notify Spiderman then

I'm not even going to try and identify it, I've never encountered something like this before.

 

[Duffer]

Looks like a nudibranch

Account Suspended

 

[Oropher]

Thank you for the link.
However it has lots of black hair, not like nudibranch or slug, kinda GHA but black.
Anyway I sprayed H2O2 to it. And we'll see whether it will grow back.

 

[reef lover]

Sponge

 

[vetteguy53081]

It is cyanobacterial blankets which create zero oxygen zones, that makes the surface turn black. This surrounded sponge within rock and is an indicator of high nitrates or phosphates.
Would make sense why peroxide cleaned it up

 

[Oropher]

Hmmm... my system is almost always 0 nitrate and 0 phosphate according to API test.