Magikarp

Magikarp is a Water-type Pokémon from the Kanto region. It evolves into Gyarados when fed 400 candies.

Trivia

 * There is medal for catching extra-large Magikarp, called Fisher.
 * Along with Wailmer, Swablu and Meltan, Magikarp is the Pokémon in the game that needs 400 candies to evolve which is the largest amount of candies to evolve in the game.