well, why don't you put two males in the same tank and see what happens if you really want to know....i'm betting they get separated sooner than later though.
in the big picture, regardless of whether or not someone has done it successfully before, you have to take into account something called "quality of life". bettas are such fascinating creatures that they demand your respect if you are going to keep them. having two males sharing tank space stesses them out and leaves them succeptable to disease. the only time that they are ever really together is when they are young and still part of the spawn. siblings will of course live together as we who breed them know from our growout tanks. when the males begin to reach maturity though they begin to search out their own space. it's genetically programmed into them to find a space to build their nest and wait for a female to mate with. once they start building nests they will fight all intruders they are physically capable of. if you go to a website called www.siamensis.com and read some of the articles on wild betta "field trips" people have taken, it sometimes takes them all day to find even a few betta nests. it certainly doesn't seem like they are all congregated in one area from reading what has been written. their opinions i hold in high regard by the way, since they are thai people who care more about conserving the dwindling stocks of wildtype than in breeding show worthy halfmoons for profit etc.
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