Betta fish are strikingly beautiful fish. They come in many shapes and sizes and they also have a wide variety of tail shapes and body color. Here are some random bits and pieces of information about Betta fish.

Betta fish are natives of Siam in Southeast Asia.
If you want an easy to care for fish, a Betta is what you're looking for.
Male Betta fish will fight each other, whence their other name "Siamese fighting fish.
Because of how aggressive they are towards one another, it's best to keep only 1 male Betta per bowl
It's OK to have other kinds of fish in the same bowl as your male Betta.
Betta fish are really slow swimmers, so if you have other fish in the same bowl as your Betta, make sure you have some place for the Betta to hide, should he need to.
What's different about the males and females
Besides the obvious stuff:

Most of the Betta's aggression is between males.
Sometimes, a new female can threaten the existing male's role and cause him to attack her.
Female Betta fish are not generally aggressive towards one another.
Just so you know how to tell them apart, female Bettas bettafishnest.com usually have much shorter fins than males
Betta females smaller than males.
Conclusion
Besides the random facts I mentioned above, here are 3 more things that you need to be mindful of when it comes to caring for your Betta fish:
About the bowl: how do you properly setup your Betta's bowl?
What are the conditions that you need to maintain in your tank?
If your Betta gets sick, what do you do to help him/ her out?
Chances are you got your Betta fish at a pet store of some kind. If you had the typical experience, you got a person that told you nothing about the proper care for your Betta.