Magikarp is a piscine Pokémon with large, heavy reddish-orange scales. It has large, vacant eyes and pink lips. Its pectoral and tail fins are white. On its back is a stiff, three-peaked yellow fin, resembling a crown; there is an identical fin on its underside. It also has long barbels. The barbels are white on a female and pale-yellow on a male. A long-lived Magikarp is able to utilize its immense splashing power to leap high enough to scale mountains. It also has a strong enough immune system to survive in the most polluted of waters. However, it is usually overlooked by Trainers because of its perceived weakness: even in the heat of battle, it will do nothing but flop around. It is believed that the ancestors of Magikarp were actually much stronger than modern Magikarp, and this led scientists to research this species.

Magikarp is found in many bodies of water, such as lakes, rivers, and ponds. However, due to its weak swimming ability, it usually lives downstream of the water's flow. It is often seen using Splash to leap out of the water, which makes it an easy target for predators such as Pidgeotto and Pidgeot. Frillish is also known to prey on Magikarp.

In Hoppy Town, there are at least 31 unique pattern varieties of Magikarp, with their scales coming in colors such as gray, black, white, purple, pink, violet, apricot, and brown. These patterns can be classified by groups, depending on how the Magikarp looks while it is still small; a specific pattern arises when it becomes bigger. Which patterns can be caught depend on the type of Old Rod; the better the rod, the more groups of patterns can be fished. The people in Hoppy Town train their Magikarp to jump the highest in order to compete in a series of Leagues to win prizes.

Evolution Magikarp evolves into .

(Source: Bulbapedia)