Fishing is an skill implemented in Pokemon World Online. Instead of fishing like the old days, there are now level requirement on every fishing pokémon. To fish you must first have a rod. The Old rod in Pokemon World Online can only be found next to the pokemon center in Vermillion City like in the classic games. Unlike the original game the fishing rod is sold for 10,000.
To fish, stand by water and click on the rod in your inventory (the items tab.) You will get a message when your skill goes up. Type /fish to check your skill.
All the fishing levels are listed below.
Level 0: Magikarp
Level 5: Krabby
Level 20: Slowpoke