I have had two kissing gourami fish for almost 4 years now. No problems whatsoever. They have a great temperament and are actually very very smart. I believe they have grown over the years to be great buddies. They are always together.
I also bought two kissing gouramis for my tank which already had two bala sharks in them. The guy at the store said that they were not aggressive. However the bigger of the two kept chasing the smaller gourami away from the food and I guess thatīs how the smaller one died. He also keeps defending the spot where some food would land from other balas in the tank. The bala sharks which are a little bigger are often pushed around by the little gourami (heīs about 5 cm long). However he has not harmed anyone.
I have a kissing gourami (named Mr. Limpet; Fish Face - like you needed to know :) which is quite larger than most I have seen. He is almost as round as a large silver dollar and lives with a plecostomus; both enjoy eating algae. I tried putting two young, smaller kissers in the tank, but Fish Face just chased them around, aggressively kissing at them. He's very territorial because once, I put our gold fish (housed in a separate, small tank) next to his and he kept his eye literally against the tank and kept lunge-kissing aggressively where he could see the Goldie! I guess he's just set in his old ways. He likes to get his fins under the waterfall from the filter and he swims right up when he sees me. The tank is in the kitchen, on the counter near the sink and he always hangs around and watches me do the dishes. I think he prefers human (the hand that feeds him) company to other fish. I now and then have to wipe off my lip stick marks from the tank 'cause I often go up and kiss right back at him - he is one of the cutest breeds of fish with a great personality! :)
I have three Gouramies (two Kissers and a Dwarf). The Kissers are very aggressive towards each other, but have now been put in their place by the single Dwarf Gourami. In my experience, I have found them to be pretty aggressive, so much that I came home to see that they had killed and were eating my Danios. But they are beautiful, and fun to watch, especially when they kiss. [Editorīs note: Kissing Gouramies are not predators. Almost any fish will eat another dead one, which doesnīt mean it killed the victim - M.A.]
I had 6 kissing gouramies, of which one was very emotional and kept kissing the others, and one by one they died. However, later when I kept 5 silver angels in the same tank and my aquarium fellow told me that nothing would happen. The kissing gourami attacked the angels also one by one and killed them. Now he lives with only a pair of tiger sharks. The time I bought the sharks they were also of the same size as the kissing gourami. However, even after two years the kissing has not grown in size and remains the same, but the sharks have outgrown the kissing by 3 times. Now I have kept my killer kissing separately in a tank with one big black angel and I feed him amply so that he grows in size.
I got two kissing gouramis in a 280 liter. One large and the other half its size. They always kiss or chase each other. They are in a community thank with angels, pleco, catfish, loaches, giant danios and lot of plants. I never had any fight or dying fish in two years. I think the impotant thing is the setup of the tank. A lot of people say don't load the tank. Well in my case I loaded it with babies of different species and they grew well together. I also feed live blood worms once a day, so no need to pick at each others fins. It works for me.