Is this algae bad?

[OblivionGamer92]

These 2 rocks are the biggest rocks in my 10 gallon and lately they've been growing algae on them. Should I remove it? I have 2 Cory catfish but they don't eat it.

 

[laoski]

this looks like the one that first grew in my driftwood in my old aquarium. i thought they were mosses or something and i jist ignored it coz i thought it would make a good decor. but it was too late that i realized they were blackbeard algae.

 

[BillD]

That doesn't look like black beard. A little like that isn't a problem. If you don't like the appearance you can turn the rocks over of remove and clean them.