I have a betta (Jack) who is the light of my life so I'm naturally very wary of what I put in with him. Personally, I have found Jack preferred to have only one of the females with him - if I add others he kills them and hangs onto the older one each time, yet he's never tried to breed with her. I have Albino Corys and dwarf gouramis. He's fine with them and has no stress at all. He hates the glass cats and vice versa, I have only just realised they pick on him so they are about to be rehomed.
Admittedly, I think Jack is a bit gay, soft and strange in the head though. The first tank he was in had neons in it and he kept eating their tails, so i rehomed him but made the mistake of putting the tanks side by sde - everytime he sees the neons in the other tank he gets rather anal and puffs himself up. Personally I think the neons called him names and he feels he needs to assert authority to let the rest of the community think hes a man.
Serious, having Jack is the best. He comes to the front of the tank whenever I sit in front of it and does little "dances" for me showing off his gorgeous blue and red hues. Despite the challenges I have had in introducing him within a community I still think He's worth his weight in gold (which probably isn't much come to think of it............" :oops: