Is this green hair algae?

[Siguun]

Hey guys back with another question. I am unsure what this is on the rock I have. It was there when I purchased it and really didn't think much of it until I was doing research and saw people talking about algae problems they were having. I thought it could be green hair algae but all the pictures I saw online green hair algae literally looks like hair where this looks like tiny green trees. Again this was on the rock when I purchased it and didn't grow in the tank. Kept trying to look for different types on algae but nothing really fit from what I kept finding online. Is this even algae at all?

 

[grassy_noel]

Tough to tell from the photo, but my first guess would be Bryopsis. You can google image search for it, it has "fronds" or "ferning" that differentiates it from Green Hair Algae.

If it is Bryopsis, there are many fewer things that will eat it in your tank, but it can be killed with fluconazole, which is an anti-fungal medication. It is sold at Bulk Reef Supply under the name Reef Flux, and many other places.

There are many threads about Bryopsis and Fluconazole on R2R.

Hope this is helpful.