The male and female betta are very easy to tell apart. Usaully, males have long flowy tails, while females have shorter but still pretty fins. Females can be housed together in the same tank. Though sometimes two girls won't get along, one may need to be removed, because they can do some really bad damage to each other. Males should never be housed together, they are very territorial and aggressive. But sometimes older males can live peacefully together. I had to males that had shared the same Bettadex with the plastic barrier between them forever. One day I just lifted the plastic piece and they never bothered each other. But I think it only worked since they had been used to each other, and they were older and less aggressive.
Betta fighting was so popular in Asia even kings were doing it. Lots of people would bet everything they had on just one fight, that's some serious betting. Bettas soon found their way to America were scientist worked and made the fancier bettas like we see today.
Bettas didn't always have their beautiful finnage and colors. Asian bettas were brown and green and had really short fins. Bettas have come along way. Now we have Double tails, Halfmoons, Veiltails and Crowntails.
We also have an array of different colors. Soon I hope to go into detail about all the differnt finnage and colors, but that will take some more research and time!