If dwarf gourami's are so aggressive, then who are they housed together?
My friend has three males in a 30g and they are fine together. I had mine with a betta and he killed him.I'm not sure that I understand the question but I'll try to answer as best as I can. Are you asking why are they housed together if they're so aggressive? Or how?
You can house a pair (male and female) in a 10g. Think of them like peaceful Bettas, a pair of males can be housed together but in larger tanks (17g I believe, along with being densely planted), since they are territorial. Girls can live together in a sorority just likes Bettas, or one boy and a group of girls.