Hair Algae in-between Zoanthids

On two of my Zoo colonies when the polyps retract I have some form of hair algae(darker green) but you cannot see the algae when the polyps are out. Does anyone have this? No visible algae anywhere else in the tank.
Adam

 

I have this also, I tried pulling it out but it regrows, my tangs occasionally eat it but I still get a few strands.

 

I did have it for a brief while when my zoanthids were first introduced. (I don't know how long you've had yours) But when after a few days my hermit crabs had a stake out near the LR thed zoanthids are on, ate pretty much everything between the polyps. The polyps kept closed for a few hours after the cleaning, but everything has been fine sence.

-G

 

The hermits really dont touch the algae on my zoanthids. Maybe its bryopsis as long as it only stays there

 

Toss in a couple of Emerald crabs and even a couple of lettuce nudibranhs if if you don't have a lot of power heads that would suck the nudis up into them ): The crabs will do a good job . It definitely is not bryopsis or the colony would be dieing off , I just lost a 180 full of corals to that pest..But any algae left unchecked will effect them in that they will stop opening to feed