Magikarp debuted in JN024, where it reeled in by Goh with help from Ash, Pikachu, Raboot, and a disguised Team Rocket and was caught y Goh after it was put to sleep by Oddish's Sleep Powder. Later, Goh used the giant Magikarp to distract a group of Team Rocket Grunts while Ash freed the Pokémon they had kidnapped.
In JN026, Goh discovered that Magikarp had grown very fat over its time at Cerise Laboratory. To fix this, Goh trained Magikarp to compete in the Magikarp High Jump Tournament. During the tournament, Magikarp was able to make it to the semifinals, where it defeated Koi Kingen's Magikarp with a jump of 21.02 meters, breaking Goh's personal record. In the finals, it competed against Kasuking's shiny Magikarp. Before the finals began, Magikarp was revealed to have had two immensely heavy weights on its back fin. With the weights gone, it jumped so high it didn't come back, and as such, its jump could not be measured, losing Goh the tournament. At the end of the episode, it crashed back down on Ash and Goh while they were on Slowpoke Island.
In JN031, Magikarp, alongside Goh's Goldeen, helped Nami's Feebas learn to swim better.
Personality and characteristics
Magikarp is a giant Pokémon, being much taller than other Magikarp. It is shown to be very powerful as seen during the Magikarp High Jump Tournament, where it jumped so high it went into space. Magikarp can be very motivated when it has a goal to strive towards.
