What is on this frag plug?

[smm52487]

Does anyone know what the red ‘branching’ stuff is on this plug? Zoas have been until today so not sure if it’s related. Thanks in advance!

 

[Ron Reefman]

Really hard to see, maybe algae?

 

[KJ]

Hard to see google hydroids.

 

[Janet Belanger]

+1 tough to see, but when in doubt clean it out! To me sorta looks like the beginnings of the mat forming purple/blue polyps. OR maaybe algae of sorts? If it's the polyps you likely don't want it, they're a nuisance softie that grows over everything. The base mat will look look purplish/red and kinda haphazard spiderweb like, polyps form and then suddenly they're everywhere.