Fishing is a side activity you can do with Bart or Theodore. You enter a fishing screen where you steer a fishing net around in the water. You get 60 seconds to catch as many fish as you can, but avoid touching the electric Chameleon Shocker that will scare away all fish currently on the screen. For every 1000 points you earn you get 5 extra seconds to play.
Catch five fish quickly without missing, to earn a temporary "Fishing-streak reward" that helps you. You get either a temporary bigger net, 10 extra seconds to play or a Juggernaught eel to help you along.
When the timer runs out you earn Pix depending on how many, and what types of fish you caught.
See the list of fish types.
If you get over 3000 points you get the Aqua Man medal.