If you do add more i might put more plants or hiding places for the fish depending on how much you have in there now. You say Lightly planted so....idk.
I know that, but i also know that keeping them in big shoals shud help minimise it.
I have been sucessful with keeping 10 but i wanna add more( i love em!).
Im also considering True siamese algae eaters over ottos once i find some. Petco has some "algae eaters" but it turned out to be the siamese flying fox...