Download McFishy 1.0

Readme

AutoHotKey (AHK), Capture2Text Optical Character Recognition (OCR), and Subtitles in Minecraft for AFK fishing despite the 1.16 nerf.
No redstone is needed, but a Mending fishing rod is recommended.

Download and install AutoHotkey.
Download and extract Capture2Text 3.9.
Download the McFishy script.
Open the script in a text editor, and change the paths for Capture2Text.exe and ocr.txt. Variable names are FullC2TPath and FullOCRPath.
Ensure Subtitles are turned on in Minecraft (Options... Accessibility Settings... Show Subtitles: ON).

Open Minecraft 1.16.2 or later.
Run the McFishy script as Administrator. A sound plays when McFishy starts.
Click on Minecraft so it's the active window.
Cast your rod in open water.
Right-click sends to Minecraft when OCR reads "Fish" in the OCR box, and again after 4.5 seconds to recast.
Press ALT SHIFT F to start OCR. Drag a box around the subtitles area. A sound plays when OCR starts.
Press ALT SHIFT Q to stop OCR. A sound plays when OCR stops. Start again with ALT SHIFT F if desired.
Press ALT SHIFT X to exit McFishy. A sound plays when McFishy exits.
IMPORTANT! The box must be big enough for the subtitle "Fishing Bobber splashes" on any line.
IMPORTANT! The box must not be too big, or OCR will be slow and fish can get away. Focus on the word "Fish" when drawing the box.
IMPORTANT! Can run in background, but subtitles must be visible. Other windows or screensavers covering subtitles will make OCR fail.