How do I know if my female beta fish want to mate?

[Fish luver]

I have two beta fish (male and female) in tanks next to each other. When the tanks are pushed close to each other both fish start flaring their gills and trying to get closer to each other.

the only thing i know is that when a female Betta wants to mate they have vertical stripes on their body's, but, the thing is that my female Betta has a very dark colored body so i cant see it, how else can i find out if my female wants to mate?

 

[SizzlinNinja]

Are they flaring in aggression, or to be show-offs? That will be key in answering your question.

 

[Vulcan]

The female would be gravid and anxious to get at the male.

 

[bakky789]

keep her in with the male for a few days or so (as long as they arn't killing each other) so when she's ready she will be in there for him to mate with. make sure his nest is built already though before you put her in. keep in mind that the male with be aggressive but will not hurt her because she's a female. if she is getting injured remove her immediately and try again another time with a different female if you could. sometimes certain fish dont click together!