Some new invasive thing...?

[KNOWYOURTANK]

They are sponges I believe
Harmless and also a sign of a good tank !

[DKoKoMan]

Looks like common yellow sponges to me. I have a bunch of yellow sponge growth in my reef as well in shaded areas.

[LifeIsGreat]

I had white versions of these little sponges. They spread around the shaded areas of the tank, so they will stay on the underside of your coral. Totally harmless. Mine came from an LFS that had some real old live rock brewing. Cute little buggers with their little siphons.

[Dearth]

Originally Posted by DKoKoMan

Looks like common yellow sponges to me. I have a bunch of yellow sponge growth in my reef as well in shaded areas.

Tippers used to have dozens in my tank before I had my cyano invasion a year or so ago

[DKoKoMan]

Originally Posted by Dearth

Tippers used to have dozens in my tank before I had my cyano invasion a year or so ago

Ughhh... Cyano takeover is the worst. I remember I had that in my very first 75g reef, definitely don’t miss that.