If you're gonna get more cories for a tank like that, find some albino cories. They're about the smallest cories that you can easily find.
I've heard that shrimp will eat fry, but they won't chase them down. If there's a dying or dead fry, they'll dispose of it.... which is really doing you a favor. I just got 5 amano shrimp and 4 cories today, and I've watched them swim right by my guppy fry without even giving the fry a glance.