Some Sort Of Green Algae Or Something?

[boberga]

As I was feeding my fish In the morning I noticed this green hair like algae or what ever It is growing in my guppy breeder box an I wanted to know what It is exactly what what it does. It seemed to pop up over night. -thanks

 

[Byron]

Not easy to tell from the photo, but I would suggest this is an algae.  As for which, it could be Spirogyra, Cladophora, or Hair Algae.  Staghorn is another similar but tends to be more "solid" and darker, so I wouldn't think this one.
 
Byron.