This fish gasping to death has his revenge on the little boy staring at him in wonder.
Do not go gentle into that good night. Rage, rage against the dying of the light.
The little boy recovers quickly from his fish smack, but the poor animal used his last bit of life force in that grand gesture. In a sweetly contradictory moment, considering the boy and his dad were FISHING, the boy asks if the fish is bleeding because he hurt it. With his head.
No, buddy. You gave him a last hurrah.