Ok, I can chime on you here. I'm a long time hardcore betta guy dealing from all sorts of fancies to fighters.
Here's what I can tell you, #1 rule is...KEEP ALL MALES BY THEMSELVES. Betta are by far one of the hardiest fish you will see alive to date on earth. All males are solitary fish, you should not even try to keep a female with it. A male will kill her even if they have bred before. It's not like any ordinary breeding pair out there that will stick together. A betta will do fine in a 1 gallon all by themselves. 8 gallon is more than enough for them. Just add gravels and some low lighting plants or a lucky bamboo tree(I prefer lucky bamboo tree, they are very helpful here).
If you want a healthy betta, I highly recommend you to purchase some IAL(indian almond leaf) overseas. Aquabid do have them in stock also. BWE(Black Water Extract) works good also, ABS(Atison Betta Spa) is also a good deal but I prefer BWE and it's best to go with IAL. It's natural acid helps reduce the betta stress and also have a tendency to reduce diseases. It is also used to heal a betta from injuries also but nothing can compete with dead or sun dried banana leaves(dead is better).