Sponge or fungus?

[harkey]

Hey guys, this has been on my live rock for a few weeks. I don’t know if it’s sponge or fungus? if it is fungus what should I do?

 

[WheatToast]

Harmless filter-feeding sponge. These are a sign of a healthy tank ecosystem. I’m pretty sure fungi never make themselves visible in marine systems unless they are infecting fish, but don't quote me on that.

 

[Jeffcb]

Looks like a sponge.

 

[harkey]

Harmless filter-feeding sponge. These are a sign of a healthy tank ecosystem. I’m pretty sure fungi never make themselves visible in marine systems unless they are infecting fish, but don't quote me on that.

Thank you so much! Still pretty new to this and it definitely scared me when I saw it lol.