Baby Feather Duster or Digitate Hydroids??

[gypsyb]

How do you tell if something is just a baby feather duster or a DIGITATE HYDROIDS?

I'm excited to see all the new life coming do in my tank, but wonder about some of it.
I saw some little what appeared to be tubes on the back of my center rock and some feathery things coming from them. They're out with the light on, and retract into the tube if disturbed.

I've also noticed now I have some small black spots appearing on some portions of my rock, and a long looks like branch appeared out of one of the blobs of slime that dissipated on my rock.

I also have some cool long black/red striped worms going. The hermit crabs seem to be having a good time.

Before I add anything else I want to know if anything should be taken out.

Thanks for any help!

 

[prow]

digitate hydroids are cylindrical in shape and their mouths are at the end. feather dusters look like daisy flowers with mouth in the middle of the flower.

 

[gypsyb]

Thank you...now if I can get close enough to check the tiny boogers out!