@BillW,
BillW wrote:
Are betta fish fights legal?
Sure. As I understand it, they fight all the time.
BillW wrote:Can the fights be bet on legally and attendance be charged for?
Probably not. What jurisdiction are you in?
BillW wrote:What are the moral/ethical issues?
Whether it is ethical to have animals fight for your entertainment/profit. That would be the main one, I think.