What is this?

[doglover]

Is this something bad or good for a mixed reef tank? I have one small piece of live rock that has it in 2 spots. Thanks for any info.

 

[Matt L]

Is this something bad or good for a mixed reef tank? I have one small piece of live rock that has it in 2 spots. Thanks for any info.

Looks like (possibly hair) algae to me. It can be removed by hand. Afterwards I suggest some snails to keep it cleaned up. Also testing nutrients (nitrate and phosphate) will help to see if there’s a problem.

 

[Gray999]

Might be hair algae, I've had many problems with it overgrowing rapidly, keep a close watch on it

 

[doglover]

Thank you, I ended up removing it all. Well, as much as I could and hopefully that will take care of it. So far so good.

 

[Tahoe61]

A lot of inverts: Snails, Urchin, Hermits, Crabs will destroy that algae should it come back.

 

[doglover]

My hermit crabs wouldn’t touch it, I thought they would eat it. They would eat off the rock right next to it but they would not touch the hair algae.

 

[get-salty]

In my experience, inverts wont touch bigger size hair algae. You will have to pull them out manually.. use a soft toothbrush. They WILL come back so youll have to keep pulling them out until your water parameter are in checked.