This algae appeared out of nowhere in a few days. It looks like long gray hair! I haven't added any new plants or fish lately, so I don't know where it came from! What is it and how fo I get rid of it?
Looks like a type of Filamentous Algae. This is usually caused by overfeeding, low CO2, and low nutrients. To get rid of it try overdosing Excel, maybe get some Red Cherry Shrimps, or some rosy Barbs. You can also blast the stuff with Hydrogen Peroxide. Turn off all filters when blasting peroxide so the water will be as still as possible.