I'm not a plant expert, but I think most any aquatic plant would be good. It provides cover and color, and I believe they even help use up nitrates.
I think the folks that surf the Planted Tanks section would be of more help though.
Good luck!
I would say oxygenators such as Hornwort, Egeria which grow rapidly, use up nitrates and oxygenate the water. Also plants like Java moss are good for fry.
Also depending on the type of fish, I suppose they would feel more at home with plants that are likely to be around in their natural habitat.
