Yes, The male blue gourami will turn dark blue and will flare his fins when he wants to breed. Gouramis are just like bettas when it comes to mating they will try to attract the female by showing off there colors and fins.
Thanks a lot, much appreciated. Also you mention bettas, are they siamese fighting fish or is that just one of the species? Will i be OK adding a SFF to my tank?
Yes, Betta is the US name for what the British (I am English, living in US) call the Siamese Fighter, and looking at your fish selection I would say it would do fine in your tank.