How can I tell what gender my Betta Fish is?

Depending on how old it is, males tend to have longer fins (usually up to 1" - 1.5" long), females have shorter, rounded fins (around .25" long). As for color, I have females that are just as vibrantly colored as my males.

The males are the ones with bright color & big sail like fins. Females are more neutral colored & moderatally endowed in the fin department....

If it's the stereotypical betta with the elaborate fan tail and long fins, it's a male. The females are fairly bland-colored, torpedo shaped fish with very short colored fins.

male betas are far more extravagant than females. Their colors are more vibrant and their tails are much , much longer. The males are generally larger in size as well.

the boys are big and have frilly fins the girls r small

Males have long fins and our very beautiful.Females are smale and kind of ugly.You would theink she is a really ugly female guppy.

Great question! 1. Males have a "beard" under their heads, a bit black. 2. Males blow bubble nests. 3. Males are more long and skinny. 4. Males are more ferocious. 5. Females don't have long finnage like nales.

the males have much longer fins

Males have way longer fins that are fancy looking...and usually they are a very bright color, whereas female fish are smaller, have short fins, and aren't that bright in color. Male betta:http://www.cbsbettas.org/images/betta.jpg female:http://www.flippersandfins.net/Images/BettaFemaleEggyA.jpg