Is it a pest?

[Dripley]

I just introduced a couple new pieces of Bushy Acropora to my tank. When I was removing it from the bag I thought a piece broke in shipment. I thought I noticed where it came from and it looked like a little piece of cotton. Yesterday I took a closer look at that spot and it looks like a little feather duster. It retracted when I restarted my main pumps after feeding my clowns. Do I need to cull it? Is it harmful to the coral? Please help me:eek2:

 

[OneReef]

Sounds like a barnacle which is not a pest

 

[Dripley]

I do believe your correct now that you brought it to my attention.