Trublion, my baby, is a really energetic and curious betta. He gets excited and wiggly whenever I stand up (he's kept on my desk) and enjoys following my finger when I trace it along the outside of the glass. He'll also jump up and try to nip at it whenever I put it over the water.
However, just a few minutes ago, he did actually -tap- my finger. I keep it well below the line of the bowl, so he wasn't about to jump out or anything, and I also keep it very close to the surface of the water so it wasn't like he had to jump far out. But I did feel him distinctly hit it.
I was just starting to get curious if it's dangerous to promote that kind of play, or if I'm mistaking his playfulness for being territorial? He never flares at me when I do it, just chases my finger and then tries to get at it when I put it over the surface of the water (both inside and outside the bowl). He's a total cutie and I love playing with him, but I don't want to end up inadvertently hurting him or promoting dangerous behavior.