Omg What Is That?

[CTS]

I was looking at my tank and found this! There seems to be 2-4 brisstle worms doing something to it. Should i remove it or leave it. Looks like a fungus!! here is a pic:

EDIT: Also my Yellowtail blue damsel is in the corner (all day) falling over to one side???

 

[Navarre]

leave it. if its food then the bristleworms will eat it.