Kissing Gouramis get pretty big, 10-12 inches. I am not sure, but they could eat your mollies. Also Kissers get territorial and are recomended for a tank of 55 gal or more. I don't know if they would bother mollies, but I don't think I would take the chance. If anyone else has any input-- I am not too familiar with Kissers, just what I read on FishLore.com. I hope this helps.