White Little Hair Like Growth on Rock

[Kacor13]

anyone know if this is good or bad. See hairy thing on left side. That’s the longest one / most noticeable in a picture. The rest are really small and more noticeable in a video. I’ve had my tank for about 1.5 months.

 

[Beau_B]

Hard to see, but my guess would be digitate hydroids.

Debatable on the good/bad. I had them and they eventually disappeared. Others have reported sustained population and mild coral irritation.