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, Larvesta, Noibat and Meltan, Magikarp is one of the Pokémon that needs 400 candies to evolve which is the largest amount of candies to evolve in the game.