IMO regular Cories don't belong in anything smaller than a 20L tank- they need to be kept in schools and need their swimming room.
fishydaze- I wouldn't consider Pristella tetras suitable for a nano tank. I have a school of 15x in my 90gal and they get pretty large and bulky for tetras- the females are larger than my Rams. They're about the size of large adult Tiger barbs (and I mean full grown ones, not the size you'd find in a pet store). They also need plenty of room to school and swim, I wouldn't keep them in less than a 30gal.