If you have had female bettas, you'll know how they love to jump.
But don't take advantage of this. It's not wise decision at all.
I have two females in a divided 6 gallon tank. I trained them to jump for my fingers to get their food.
My oldest female, Kyu, now is a freaking kamikaze. She leaps at everything now. When I open the little feeding hatch to feed her and her neighbor, Nya, she leaps clear out of the tank before I even bring the food close to her tank. Just recently, she learned how to jump over the divider now, which goes about a good inch above the water level into Nya's half of the tank, giving me a few good freak outs and I desperately try and fish her out to put her back into her half.
But no, as cool as it is to have your fish leap for your fingers, do not encourage this behavior.
Betta fish are too smart for their own good!!! xD;
;_; let this be a lesson to you all! lol xD
[edit:] AHHHH!!! I just had to lower the water level because she did it AGAIN!!! Crazy fish!!