Who Gives A Fish Forums

Agree with haywire on group size. Also, add them all at once if you can. Introducing a few at a time can stress the new ones and the existing school. I made that mistake once, and it took weeks for them to settle.

Harlequin Rasboras are another great pick. They're hardy, peaceful, and their red coloring pops against green plants. Mine school near the middle of the tank, which adds nice movement without crowding the bottom where your Corys hang out.