I’m genuinely surprised they got breeding that fast. I always heard they were easy to breed but wow.
Based on other fish or animals, the biting is likely to immobilize the female so that they can breed with it. Others know more about puffer breeding than me though.So for them the act of mating is biting ? Only biting nothing else ?
I am pretty sure it hurts them. Mating in nature is not always a nice cuddle.