Hair algae, no matter whether green, black or brown is an unwelcome guest in any aquarium. It grows on any surface and stops plants from thriving. Its especially virulent when there’s excess light or nutrients. Fight back with Anti Hair Algae. Anti Hair Algae kills off this troublesome pest by starving it of its preferred nutrients. Use for removing unsightly green, brown or black hair algae growing on plants and ornaments in your aquarium.