Suggestions for animals in a river tank

[Jack]

I'm giving my kids a 29 gal rivertank for Christmas. I've got a lot of experience with fish, but none with reptiles or amphibians. I'm interested in keeping some reptiles/amphibians, but not sure what would be best and easiest for this type of environment. I realize I will likely have to feed some live food, but would prefer animals that will take some prepared foods or at least don't feed so much that I'm constantly having to run to the pet store to pick up more live food.

About the tank: The water section will be heated by an aquarium heater. The tank has a glass top, which is again covered by a screen top. The glass will cover all but 1"-2" of the tank (which is why I also have the screen). Lighting is a strip light with 2 20w flourescent bulbs. If additional heating is necessary, I'll add an incandescent bulb or a heating pad to the back of the tank.

Anybody have this type of setup or have recommendations for good animals to keep under my scenarios?