Just keep swimming, just keep swimming, what do we do? We SWIM SWIM SWIM!

Horizontal swimming <--- ----> will quickly get your fish disabled.

You want to pick a spot to swim vertically as the mode will teleport you from top to bottom and vice versa.



There are multiple spots where this will be doable but for ease of aligning up with an item spawn I try to line up with the "Bay" in area 3.



Hold down "W" or "S" key or the UP or DOWN arrow key and the fish will swim to you, and you just watch the coins roll in.