Orange growth on rock

[Joshua2598]

I've never seen this on my rock before. Tank is about a month old and this has appeared in a few spots seemingly overnight.

 

[BestMomEver]

Sponge? Dunno but I’m sure someone does!

 

[mta_morrow]

Looks like a sponge starting to grow. Good news!

 

[Brew12]

If I had to guess, I'd think it is either a type of diatom or a type of cyanobacteria. Until it gets bigger or you put it under a microscope it isn't more than a wild guess.

 

[Joshua2598]

There are about 3 or 4 different spots where I saw this growing in the front of the rock

 

[Joshua2598]

I believe I had a sponge in my tank a few weeks ago on the tiniest piece of live rock. It died a couple weeks ago because it had no food but I recently started dosing live phyto.