Algae?

[GammaYankee]

Hi everyone,
I noticed some white hairy stuffs on my rocks. At first I thought it was some dying algae, since I was dosing reef flux. However, after four weeks, they are still there, while my GHA are all gone. Any idea what they are? Thanks!

 

[york1]

hydroids or maybe the start of bryopsis

 

[Jikkermanccini]

Looks like hydroids or bryozoan to me. Cool little critters, they look like cryptic species so there's not a risk of them stinging coral or anything.

 

[GammaYankee]

Thanks for the replies. I think it's most likely hydroids, since I have just dosed the reef flux, which killed all the GHA and bryopsis in my tank.

Did a quick search on hydroids, they seem to be terrible pest. @Jikkermanccini Do you have any experience with these critters? I did have a few Acros on that rock that died over night. Now I am suspecting that my Acros are stung by these hydroids.

 

[Jikkermanccini]

Thanks for the replies. I think it's most likely hydroids, since I have just dosed the reef flux, which killed all the GHA and bryopsis in my tank.

Did a quick search on hydroids, they seem to be terrible pest. @Jikkermanccini Do you have any experience with these critters? I did have a few Acros on that rock that died over night. Now I am suspecting that my Acros are stung by these hydroids.

I have had hydroids in the past, but they never bothered much. They died back after I stopped dosing aminos and started feeding less, and now they're gone in my tanks. Don't know if you'll get the same mileage though as I had a different species.

 

[jcook54]

Those are digiate hydroids and I've never seen them be a real issue. Their population can fluctuate and they will sting corals but they usually go away on their own. Colonial hydroids are the really bad one's in my experience. They're typically tan or brown and grow in big colonial clumps. I'd limit feeding any sort of powdery coral food and see if that helps. If you don't feed any of that, limit frozen food. Anything that corals might like to eat, hydroids will too. I second @Jikkermanccini observation - I had the same things and they went away on their own without me doing much of anything beyond limiting nutrient inputs.

 

[GammaYankee]

Thank you guys! @york1 @Jikkermanccini @jcook54. I will limit my feeding and see if they go away.