Hmm, the tank is a bit too small. I recommend 20 gallon minimum and max is more than 1,000 gallons I guess.
I have gouramis 3 males and 1 female in my 29 gallon tank, with my other fishes and they seem to work out fine.
My 500 gallon has an abundance of different types of Tetras, Angels, and gouramis
So I suggest you get a bigger tank and move your gouramis into the bigger tank, because you don't want to have a lot of stress build up.
Also, they are from India (Hindu stan) and they live in very very warm waters.
They live in rivers, lakes, and sometimes streams.