Brown algae?

[Waikle]

Hi there, this may be a stupid question but here goes... I discovered in my aquarium recently that there are two colors of algae growing. Or maybe one isn't algae, I really don't know. One is a bright kind of limey green and the other is dark, almost a brown. Are there different kinds of algae and are they all ok or are some not so much? If there is such a thing as "bad" algae how do I get rid of it, apart from routine cleaning?

 

[sinibotia]

Algae comes in practically all colors of the rainbow! The color of an algae depends on different pigments it has to help it capture extra light or dissipate harmful excesses of light. There are some toxic algaes and parasitic algaes (in fact the fish-attacking "fungus" saprolegnia is actually an algae) but in general all of the algae that grows in your aquarium is not harmful, just aesthetically unappealing!

 

[Drakmanka]

I get that same kind of brown algae in my tank when I leave the lights on too much. I know it's native to my local water, as it blooms in my local river every summer when the water gets too low. Before my catfish ate all my snails, they loved it, so I don't believe it to be harmful.