i have had a dario dario (also known as a scarlet gem badis) for almost a year and i keep him in my nicest tank with my threadfin rainbowfish, a powder blue gourami, and some cherry shrimp. everyone always gets along just fine.
so i decided to add a betta (thinking i may need to watch in case the betta and the gourami have any issues) because i just think bettas are awesome. everything seemed fine till about a week later when i was watching the betta aggressively chasing the little badis. i quickly moved the betta to another tank, thinking he was an overly aggressive betta.
a few months later i tried the same things, again. i added a betta, and yet again, a week later i noticed the betta chasing the badis.
i've heard of bettas chasing gouramis and fancy guppies, but all the ones i ever get are quite happy living aside said fish.
while at the same time, i cant find anything about the badis, yet it is consistantly happening everytime i try >.>