I honestly prefer Magikarp and Gyarados, because of what they're based on.
In the wild, koi are cold water fish who gain strength by swimming against currents. It seems they have captured the imagination of fish fanciers for centuries. Many years ago, in a time before recorded history, a huge school containing thousands of koi swam up the Yellow River. The colors of their well muscled bodies flashed in the sunlight making them seem like a million living jewels. All was going well until the koi reached a waterfall. Immediately, a large number of them grew discouraged and turned back, finding it much easier to simply go with the flow of the river. Yet, a determined group of 360 koi stayed on. Straining and leaping, each koi strove to reach the top of the falls. Again and again they flung their bodies into the air only to fall back into the water. All this splashing noise drew the attention of the local demons who laughed at the efforts of the struggling koi. Adding to their misery, the demons sadistically increased the height of the falls. Still the koi refused give up! Undeterred, the koi continued their efforts for one hundred years. At last, with one heroic leap, a single koi reached the top of the falls. The God’s smiled down in approval and transformed the exhausted koi into a shining golden dragon. He joyfully spends his days chasing pearls of wisdom across the skies of the vast and eternal heavens. Whenever another koi finds the strength and courage to leap up the falls, he or she too becomes a heavenly dragon. The falls have become know as the Dragon’s Gate and, because of their endurance and perseverance, koi have become symbolic of overcoming adversity and fulfilling one’s destiny.
tl;dr Magikarps, as weak as they appear, gain their strength by swimming against the currents, and that strength is what helps them evolve into Gyarados.
It's a message about overcoming obstacles in your life.
Those of you who are very close to me on here know that one of the biggest obstacles I had in my life was my mother being an unfair person (that's the nicest I can say it on here).
I have overcome my obstacle of her, and because of that, it has made me a stronger and more independent person.
I understand the hardness the Magikarp has to go through to become a Gyarados.
It's because of this that I'm getting those Pokemon tattooed on me one day.