About that Red Encrusting Algae (not Cyanobacteria)...

[Tay Kendall]

I've been curious what this is, but I'm not 100% sure. Anyone have an answer?

 

[Devaji]

I've been curious what this is, but I'm not 100% sure. Anyone have an answer?

I wonder if it's blue plating sponge just red in your tank?
there is a Red Branching Photosynthetic Sponge but its branches not plates.

soooo IDK