With the recent English version of the Magikarp song released I decided to check Youtube for other Magikarp music videos, here is what I found.
The Magikarp Song
First we have an official Pokemon song from The Official Pokémon YouTube Channel
An ode to one of the greatest (and weakest) Pokémon of all: Magikarp!
Celebrate the beloved Pokémon and sing along to the Magikarp Song!
"Magikarp" A Pokémon Parody of Wrecking Ball - NateWantsToBattle
The title says most of it here, a parody of Wrecking Ball. This song shows the feelings of a Magikarp wanting to be strong and be caught, but is ignored do to it's low stats and weak attacks (when it gets then).
The Magikarp Song: A Pokemon Shanty (Game Parody)
The story of a fisherman trying to catch a Pikachu with his Magikarp team.