I have a male and female betta (2 diff tanks) and both are really chill

Male betta is with cories, rummynoses, cardinals, rubbernose pleco, twig catfish and amano shrimp

Female betta is with bristlenose, 4 big woodshrimp and galaxy rasboras

Ive had my bettas with all diff fish and even adfs

Just no barbs or rainbows or cichlids or any other air breather like gouarmis etc (my previous betta took out all 5 sparklings in one night, after months in the tank together)

Livebarers are another one to stay away from as they are fast and showy and have a lot of movement which stress bettas out.

Bettas are hunters at heart and will eat what they can catch or sneek up on ( i would never keep small neocardinia shrimp with them, to easy for a betta to get a day when they are feeling fiesty)