I have 2 dwarf gouramis which I have had for awhile, but lost a couple before my present pair. I went to the shop and asked for two gouramis, and they sold me two males, a blue and red. They literally nipped each other to death. I asked the shop why they sold me two males as they are constantly attacking each other but apparently it is rare for a blue dwarf gourami to attack a red gourami …. Anyway they gave me a female gourami to add a bit of sex to the mix but it was too late for the two males and I eventually put them out of their misery.
I did not add another gourami to my tank to ensure that there was no gourami specific disease in the tank after which I added another red male dwarf gourami and he has been peacefully living in my tank with guppies, cardinals etc. He is a bit pugnacious (as described in a book) towards the female dwarf gourami but apparently, that is normal.
Therefore I figure that it is risky adding two males in the tank but they do like a chase, so add a female otherwise they may chase something else
the above is the full extent of my knowledge, take from it what you will
LOL