Is it a Fluorescent light or incandescent light??? Is it centered over the tank or to one side?
Anyways, plants I like to see in 5G are Coffeefolia (Anubias barteri v. ‘Coffeefolia’). This is a good background or centerpiece plant for a 5G because it gets to a max size of 5-6". I have a Cryptocoryne becketti as my center plant along with the driftwood.
I also have Jungle Vals (Vallisneria gigantea). These tend to grow out instead of up (at least for me) - which is good because a 5G is not very tall. Further, I have Asian Ambulia (Limnophila sesiliflora) and Cardinal Temple (Alternanthera cardinalis) in my 5.5G. For ground cover, glosso (Glossostigma elatinoides) is good as well as clover (Marsilea quadrifolia or Marsilea mutica).
HTH
Aries
