Thats a huge lie!!!
The world of plants is so broad, there are plants for every kind of tank.
What is the setup? And what lighting do you have over it?
Some plants which are fine in low lights are: Java Ferns, Dwarf anubias, Java moss.
I reccomend you look at the pinned topics. An extra light fitting requires a controll unit which usually come for 15-25 pounds. Then you buy a fluroecent tube which come between 5-15 pounds.
This might not be neccesary in your case if you already have some "OK" lights.