I wouldn't advise it. I have seen it done by my grandfather...including multiple males. But he had custom made tanks that were very large. They were likely a shallow (12") 100 gallons. And heavily planted means HEAVY with peekholes to see your subjects doing their daily business like a biotope species tank. 8)
Also he wild caught his specimens personally all from the same areas.
Most don't have the space or like labyrinth fish THAT much. And large groups of bettas that hang out in nature or at a breeders are normally spawn siblings that missed the aggression boat.
And.. a female is MORE likely to shred up your male than the other way araound. They also are faster than fancy males and can strike hard as well as bite. A really large or aggressive female can permanently damage your male. Females will flare and fight each other too. 8O :?
Most don't have that kind of floor space or like bettas and labyrinth fish (imagine that times the number you wanted the harem to contain...)
Add to that that most bettas bought are unrelated and jar raised (which raises aggression as well as saves beauty).......? Nope...nope!
The theory is there but the execution is usally fatal..
There are many gourami betta species that are more socialable, but if you want more than 1; avoid splendens and coccina most of all. Avoid imbellis too, pure wild form are hard to find. most have been crossed to coccina and splendens as fighters and released back into the paddies or sales jars after they win/lose. If the experiment fails you have to figure out how to seperately house several bellicose fish. Or (like the 3 free import girls my daughter has almost became) the can be...oscar snacks.
HTH
