View Full Version : Black Algae?

10-21-2008, 09:39 PM
I'm new here and I have a male Betta in a 2 gallon tank at my place of work. His name is "Leon". I always keep his tank clean and just lately have noticed that there is a black substance on his "hiding cave" and some of the artificial plants. The substance almost looks like charcoal. I've cleaned it once by scrubbing it off but it has come back. What should I do? Is this harmful to "Leon"? Thanks for your help.