ID Help Please? Green thing

[soondubu]

this green growth came on my latest live rock addition.
what is it and can i keep in in the main tank?

 

[zap800]

looks like green hair and alittle cyno..........................not good or wanted

 

[viet-tin]

could be maidens hair:notsure:

 

[thomas712]

You might also look up Bryopsis

 

[viper_930]

Yea, I think it may be bryopsis. It looks similar to what I had.

 

[soondubu]

so if it's bryopsis or maiden hair, it's okay?

 

[thomas712]

The problem with bryopsis is that almost nothing will eat it, it can possibly get to plauge levels and choke many things out. There is a slug that eats it though. No bryopsis is not a good thing at all and very tough to get rid of, think of it as hair algae gone mutant.
The maidens hair that I have seen is bright green and most people would only keep it in a refugium for nutrient uptake, but not in the display.
Thomas