Free credits option:
Complete fishing in all locations and stages in World Monsters Fishing to unlock the "Free Credits" option.

China:
Finish all levels in world challenge mode to unlock the China level.

View statistics:
Press Up(2), Down(2), L1, R1, L1, R1, X, Circle at the title screen. A sound will confirm correct code entry. Press Select at the options screen to view your statistics.

Big Fish:
Hold Triangle + Circle + Square + X + R1 + R2 at the lure selection screen. Go to practice mode, then go to the next island on your right. Go to the hus where you will find many very big fish.

Alternate challenge:
In the live well on the main menu, where your largest fish are kept, is a pocket for every one of the fish found in the game. For an alternate challenge, Try to catch all of the fish, then try to reach the monster ranking on each . You will know when you catch a monster fish because a crown will appear near the fish. When you select the fish, and the fish you caught appears, the announcer will shout "Monster!" (as the monster stamp will appear over the picture).

Unlocking levels:
To unlock two hidden lakes, simply fish. The first lake is Kitaura and it opens at 100 fish. The second is Lake Yamanaka and it opens at 150 fish. Note: In the game, the count is by caught fish not games -- continuing repeatedly does not work as the fish count will still be zero. To see the fish count, highlight the save on your memory card.

In world fishing mode, you do not have to finish the Comoros level before the second three sites are unlocked. Clear just the U.S. and Japan levels and the other three levels will be unlocked.