Minecraft wiki entry for Fish_farming, associated text: Snapshot 20w49a added the Sculk Sensor‌[upcoming: JE 1.19], which powered a new generation of AFK fishing farms. A design by Rays Works uses skulk sensors to detect a bobber sinking into the water when loot bites, triggering the sensor and forcefully causing the player to reel the bobber in via trapdoors activated by a skulk sensor.