There is no wild carp king and Tyrannosaurus Rex (carp dragon) in Pokemon black and white. You can only use 500 yuan to buy a Magikarp from an uncle at Miracle Bridge.

If you are skilled, it is recommended to learn to climb waterfalls+dance dragons+teeth of ice+earthquakes.

Climbing waterfalls and earthquakes are learned through skill machines. The tooth of ice and the dance of the dragon Tyrannosaurus Rex were 32 and 44 years old, respectively.