The largest species of Gourami is aptly named the Giant Gourami and can grow to over 2 ft.
I used to be fascinated by the various gourami types because of their unusual breeding habits in which the males build floating nests of bubbles and also because of their unusual appearance. I like to watch how these fish use their 'feelers' and also how they rise to the surface to gulp air from time to time. All gouramis are Anabantid or Labyrinth fish, and have the ability to survive in water that is low in oxygen because they can also make use of atmospheric air to breathe. This ability is linked with the bubble-nest huilding of the male gouramis too.
I never had any Giant Gouramis in my collection because I knew they would grow too big. I used to like to see them in the show tanks at the local aquarium shop though. I used to dream of one day, when I was grown up, of having big enough tanks to keep these massive fish in, and all the other very large species of tropical fish that you can get. Not having the space meant that I had to be content with keeping Dwarf, Thicklip and Blue Gouramis, the species that could be housed and bred in aquariums that I could afford to have and that my mother would allow in my bedroom.