HELP, no idea what these are (ID REQUIRED)

[garra671]

so i cleaned out my skimmer the other day (scrubbed out the neck and such) and now today i find all of these lil... feather duster looking things attached inside my sump (i have a crab that lives in there) they look like feather dusters but i just need to be sure to know that they are harmless; i dont think its algae since i have no lighting running on my sump as of right now. the small bubbles on them are air, the "pest" itself is a tannish/clear ball almost with what looks like a feather duster head poking out of it.

 

[pugcrush]

pineapple sponges; they're harmless

 

[bozo]

^ looks like sponges. Learned about their anatomy and life cycle in an invert zoology class in college. Harmless as pugcrush says.

 

[Taservices]

I know I'm late to the party, but they are sponges. Harmless and will boom/bust on their own in the sump. You can remove them if you want to stop them from disintegrating back into the water column, but the difference would be moot.

 

[TCB.Reefer]

I got em too....neat little things