Feather Dusters Gone Wild

[johnd4g]

I've noticed an unusual outbreak in my tank that started a couple of months ago. Feather Dusters!!! Hundreds of small Feather Dusters in my 25 gal nano. In the pic below (yea poor quality) you can see dozens of them (along with a small piece of macro algae) growing on the front of some rocks. They look cool, but I'm getting worried they are becoming too numerous. I do 20% PWCs about every ten days and water parameters are in check. All livestock are doing well.
Any thoughts?


Thanks!