1) This quest starts with any Fishing Guild Member in any town. This particular one was in Rune. Most are found in the Grocery stores. He tells you which mobs to hunt for Sweet Fluids (quest item, not tradeable) to trade for Fishing Shot.
The mob list includes just about everything, everywhere, but here is the complete list anyway.
Talking Island
Elven Village
Dark Elf Village
Orc Village
Dwarven Village
Kamael Village
Gludin Area
Gludio Area
Dion Area
Floran Area
Giran Area
Heine Area
Oren Area
Aden Area
Hunters Village Area
Rune Area
Schuttgart Area
2) When you have some sweet Fluids go back to any fishing member to trade for fishing shots.