I would strongly suggest the Trichogaster leeri, Pearl Gourami
. I breed them here for many years and are the only totally peaceful gourami of them all.
I read somewhere else that only one male can be present in the group and I say this a complete nonsense. My 360 litre has at this moment, 10 gorgeous youngsters together.
My breeding tank has always three males and three females and they go along very well, without one occurence of violence; in fact, the colour display is stunning and they "compete" with each other to show the best attire possible.
For me, its the most beautiful of all aquarium fishes, including Discus
Given excelent nutrition, a well balanced aquarium and enough space, they are splendid to see and easy to keep.