are snakes immuned to their individual venoms. i mean when two are fighting?

Answer 1

You got to scroll way the heck down to where it says immunity but it says this:

"The question whether all snakes are immune to their own venom is not yet definitely settled. Most snakes certainly are..."

Answer 2

No, they are not. If a venomous snake accidentally bites itself while pursuing prey, it may succumb to its own venom. Some venomous species, cobras for instance, feed primarily on other snakes. If they have a snake-killing venom, it stands to reason that they could be killed by it too. In fact, cobras will kill and eat smaller cobras when they have the opportunity to do so.