Use a quick, decisive method to minimize suffering
For small fish, place the fish in very cold water mixed with ice until it becomes unresponsive, then confirm death
For larger fish, use a sharp blow to the head to render it unconscious immediately, then bleed it out if appropriate
Keep the fish out of water only as long as necessary
Do not let the fish suffocate slowly in air
Do not use methods that cause prolonged pain or distress
Confirm the fish is dead before disposal or preparation