Be wary of it. In the last 6 months I have had TWO male stowaways that somehow made its way into my sorority tank. Both also looked nearly identical to your pictured betta too. When they're small they are sold (erroneously of course) as "females" but then after a few more months their male aggression comes out.
On one occasiona after I raised the temp of the tank above 80F the male started blowing a bubble nest and courting one of the females in the tank! I definitely put an end to that with the fishnet immediately...