There are two species of smaller cory (actually, there are more than that, but there are two that are easy to find): C. Hasborus (Dwarf Cory) and C. pygmaeus (Pygmy Cory). They are both toxically cute. I have a dozen pygmies in a 20 high with 8 neons, some ottos, and a small bulldog pleco. They love to hang out on plant leaves. Couple of things about the little ones: they are still mostly bottom dwellers, but they get into the midwater a lot more than the bigger cories. Also, they prefer to be in large groups. Regular cories you should have at least 4 to get true cory behavior, the smaller ones at least 6. When I was reading up on pygmies, I found that they would school in the hundreds.
The plus side of this is that, for the space 3 full sized cories take up, you can house 9 pygmies - they top out at an inch.
What else have you got in that tank?