This is not legal in most places but theres talks of other animals fighting so why not ask.
I know it is popular with Bitcoin and gamblings.
As much as I want to be completely unbiased towards the act, I am against any kind of gambling which involves animal fighting. I do not support these kinds of activities as they embody and reflect on what kind of society are we in the present days.
If there are people supporting/gambling in this type of event, I kindly ask to reconsider their decision and realize that there are various of gamblings around the world. Dog fighting or any kind of dangerous sport which involves killing does not have to be a type of gambling.
I don't think I can stand watching two dogs fight each other, of course, dogs also fight, but when you put two dogs in betting, the organizers will make sure that anyone of them will get killed to have a winner, I think they are using drugs and undergo these dogs to harsh condition so that they become wild.
At the end of the day, regardless on whether they are animals or not, if it involves life/death then I am completely against it. Respect for animal lives will reflect the character of our society and shape on what we want in the future.