It won't, b/c it'll rarely, if ever, be on the side of the tank. They won't eat the algae off the side of the tank.
I'd get em from a breeder. I bought some from Unungy at Unungy.com three years ago with the hope of getting a spawning pair-- but I think he sent me all males. Liveaquaria.com has them too .. but they are super expensive on that website.