Otocinclus are for you my friend. I have a few in my tank and they are hungry little fish that love all kinds of algae. They don't grow very big and they are armored. I keep them with some angelicus loach and they get along just fine. They keep my plant leaves nice and clean without damaging a single leaf.
I would put three or four in there. They arn't the most interesting fish. You probably won't see them very much but they are awesome at removing algae.