I had 9 red serpaes in the tank before. I added 12 cardinals today. The angel hasn't touched any of them yet. They're still small so I hope raising them together will make it alright.
An old wizened fishkeeper once told me, "If a fish in your tank is small enough to fit inside another fish's mouth, eventually nature will take its brutal course."
12 cardinals are doing just fine... they school and somethings run around whent he angel floats by. i'm done stocking my tank right now 12 cardinals, 1 angel, and 6 cories. pretty full for a 29g
I think Harlequin Rasboras look gorgeous in a tank. I've never seen mine nipping at anything but food. They may not get as big as the fish you had in mind, but you can just get more of them.