java ferns are one of the low light species and are very hardy plants they can live with almost no light......if u have driftwood in your tank you might want to look into java moss which will cover the wood in no time and doesnt require much light either
Java fern, Java moss, willow moss, Elodea densa as surface mats, Ludwigia repens, anubias, pygmy chain swords all do well in low-med light without additional CO2. Between them you can make a nice display.