I spent one night with my sisters after dinner just coming up with ideas on what to name my fishie, many of them were good, I guess Kitkat stuck because he's red and it's my favorite chocolate XD not that I would eat my fishie, no way! But yeah haha
I choose Kaoru because I wanted to go along with my fish naming theme and I wanted to name her after a strong character in hopes she'd live. Kaoru is the female lead in the Japanese TV show GARO. Kaoru from the series was set to die after a hundred days but the male lead fought to save her from her ill fate. Funny how Kaoru the betta seems to fit her name so well in both surviving so long and behavior traits seem to match.
I also call her tadpole, because she literally looks like a tadpole to me.