Yes, Bettas and Gouramis are the same family. In fact Bettas are a member of the Gourami family. They will react to Gouramis the same way that they will to having another Betta in the tank and a lot of time the Gorami will react the same way. They will both act in a territorial and aggressive manner. It is VERY possible that one or the other will kill the other. There have been reports on this forum recently of both fish being killed by the other type of fish. This is just not going to work. And Butterly is right, 10 gallons is not an adequate size for 2 gourami. They will fight each other if they feel they are crowded. Aggessive fish always become more aggressive the more crowded they feel they are. You may be able to have one or the other, one betta or one gourami but that would be the limit. Perhaps 1 betta with some corries or otos to control the waste (cories are not algae eaters but otos wil eat algae if you do not overfeed them)
This is just a suggestion the decision remains with you.
Rose
