Another thing you could do is get some small minnows in a school and maybe even darters, wich are very cool. If you do get darters, catch them first before any other minnows because they are quite hard to get into the rythm of feeding and need live foods at first, but can eventually be weaned into frozen. Provide them with a strong current and plenty of hiding places (rocks, wood, ect). Natives will generally need quite a bit of oxygen, so get either a few air pumps or live plants. I don't know if louisiana has them, but there are fish called dwarf sunfish that live in florida and would be compadible with smaller minnows and darters. Don't get any crayfish though, because they will catch and eat any fish that won't eat them.
So I think a few schools of different types of minnows and a couple darters would be really cool. Just to see what kind of small fish you have, you can make this easy minnow trap
Make your own minnow trap -- Boys' Life magazine and take a picture of the fish caught, then do some reasearch on what they eat and how big they get.
Oh I wish I could have a native tank, but I just don't have the time