Information from Bulbapedia:



"As of Pokémon Platinum, Magikarp is the lowest, and ironically, also the highest level non-glitch Pokémon available for capture at level 1 and 100, beating out even the level 80 Arceus for highest. It is only available in a pond in the Resort Area with a Super Rod in Platinum, where only Magikarp can be caught and range in level anywhere from level 1 to 100. "



Unfortunately, Magikarp is the WORST Pokemon to obtain, at least until you evolve it into the powerful, intimidating Gyarados.



For those wondering why Magikarp is a very horrible Pokemon to get is due to its abysmal stats and poor movepool, learning no moves from TMs & HMs, no effective moves until level 15 and learning only one, and probably the most effective, through tutoring.



Magikarp starts with these base stats:



HP: 20

Attack: 10

Defense: 55

Special Attack: 15

Special Defense: 20

Speed: 80



Although scoring an average for Speed and a "fairly well" for Defense, the only way to let your Magikarp level up without the use of Rare Candies is to use the EXP. Share and let your Magikarp level up by making any other Pokemon in your party battle.



To compare Magikarp with its evolution, Gyarados, here are its base stats:



HP: 95

Attack: 125

Defense: 79

Special Attack: 60

Special Defense: 100

Speed: 81


Gyarados can use many strong Dragon-type moves, but very little Flying type moves even though it is of that type. It also learns HM and TM moves, like Surf and Water Pulse.

I hope you enjoy evolving your Magikarp, that is if you caught one. - Chatot.