Change lure color:
Press Up or Down in original mode to choose a alternate lure color. 

Sonic lure:
Successfully complete all five professional tournaments in original mode. 

Female character:
Press A + B at the arcade mode level selection screen. 

Alternate clothes and boat color:
Reach the final tournament in original mode for new clothes and boat color. 

Secret practice levels:
Successfully complete the game once in arcade mode. Three new levels will be
unlocked under practice mode. Successfully complete Lake Paradise in original
mode to unlock the Palace level in practice mode. Successfully complete Lake Crystal
in original mode to unlock the Falls level in practice mode. 

Hint: Keeping low line tension:
After your tension gets up very high in red, sweep the Analog-stick in clockwise full
circles. If done correctly, the tension will go down extremely low, allowing you to reel in
big fish. Keep sweeping the Analog-stick to cause the fish to become tired.