How do you tell a male beta from a Female?

[Joeyt66]

I am new to this betta thing and they are so nice looking i would like to have more then 1. Can you keep a male and a female together for more then breeding? Can you keep 2 females together ? How do you tell a male from a female?

 

[SConrad]

Male bettas have longer fins, and females have short fins..simple as that? kinda...
If you're just thinkin about veiltails then yeah, it's simple as that...but plakats and some other betta types have short-tailed females..here is a pic of my female..but she and my other one died like 2 days ago

I kept two females together in a ten gallon with a few other fisha dn it was success, but it's best to keep about 4 females in a ten gallon together....I wouldn't try putting two females together in a smaller tank then 10 gallons...
Don't try to keep the male and female together, he will become aggressive towards her.

 

[braxenburg]

You cannot keep a male and female together for other than breeding.Your taking your chances putting them toghter for breeding in the first place. One male does nicely by himself. You can keep more than one female toghther they do well in a community tank, unless you get an aggersive one!

 

[cation]

Male bettas have longer fins, and females have short fins..simple as that? kinda...
If you're just thinkin about veiltails then yeah, it's simple as that...but plakats and some other betta types have short-tailed females..

That's why fin length is not an effective way to determine sex. do a search for ovipositer - it's a small, white tube that looks like a dot behind the ventrals of a female.