I don't actually know what a fishmonger is to be honest

BASICS:

WASD to move
1-7 or arrow keys to equip different fish
Space to begin fishing
Point and click to shoot
Enemies will spawn in the corners of the map in increasing numbers and at decreasing intervals
Survive as long as you can!

FISHING:

Space to begin fishing
Press space when the fish is overlapping the green bar to catch it.
You cannot fish while moving
Hooks make fishing easier
Swordfish protect you from the next hit you take