I was going to get 3 for my 10g but after what you said about them starving I think I might only get 1 or 2 and switch to plantastics so they'll eat their fill, what do you think about that? I also have flourescent lighting(and lots of it), so I might switch to incandescent, too.
By the way, I only have very few plants already and I'm going to add a microsword and one more plant soon so long as you think the oto(s) won't starve