What does brown algae look like?

[Musket]

Since adding a light to my goldfish tank, whom only got morning natural light before.... I have this brown stuff... It's soft and wipes off the glass. It stopped for awhile and now I see patches of it on the bottom big rocks but not the gravel and inside the bettas bed (a styrofoam cup floating on it's side)..

What do I do to get rid of it? Anything eat it? Bristle pleco, snail??
Thanks in advance.

 

[Apocalypse_Gold]

Otocinclus cats are the best at eating brown algae, or diatoms. My concern with them would be they are sensitive to water conditions and goldfish are ammonia machines.

 

[Musket]

I also have a male and female betta in there, triple filtration (undergravel, hob, sponge) and do weekly water changes so it may be okay.