I have eight bettas right now. Technically, some are family fish or y sister's, but that's how many I now right now. I've had ten bettas total. I accidently killed my first two females, as I didn't know that they fought. They killed each other, but now all my females are in solitary confinement.
3.5 gallon-Splendens Stelleri, the School Betta 5 gallon- Bluejay 20 gallon long--5 platties and Cleopatra. 2.5 gallon- Rose 55 gallon- 4 gerbils