Can anyone help me figure out what this is?

[candelloro]

My tank has been running for almost 4 months now and suddenly these started appearing on the back glass. Anyone have any idea what it could be?

 

[Tahoe61]

Possibly a branching Hydroid type. Are there little tuffs at the end of the branches?

 

[Proteus Meep]

Possibly a fixed branching Foraminiferan

This reefer had them on the glass and look quite similar to yours

 

[candelloro]

Possibly a fixed branching Foraminiferan

This reefer had them on the glass and look quite similar to yours

Are they harmful?

 

[Proteus Meep]

No not harmful..just a part of your tanks divesity

 

[brandon429]

Pretty rare I’m jealous. Not for the ocean in general but for our tanks to be branched like that / mini coral look