How do Bettas (or Siamese Fighting Fish) kill each other?

[Darkness Decends]

I know that Betta fish attack each other by slapping each other with their fins.

But in the wild, there is no fight to the death, the loser usually runs (or rather, swims) away.
But in a fish tank, there is no escape, and so the winner keeps attacking and dogging the loser and then killing it.

What is it that's so lethal? Is it the stress on the loser? are there barbs on the fins? Does the loser suffocate in the fins? Does the winner bite or tackle the thing until it gets a wound lethal enough for it to die?

I'm just so effing curious about this. Dx

 

[Ashley]

they bite each other


i use to breed betta but after my fav. male almost got killed i stoped

 

[Adalwolf]

Basically one if them die from being wounded too much.