The Aubir region is home to the largest known coral reefs in the Pokemon world. This reef has become home to many unique species, and in some cases new variations of common pokemon.
In the great aubirian reef, Magikarp has finally found its ideal nich. Magikarp has formed a bond with local mareanie, the fish sharing it's food with the mareanie and in turn, the mareanie giving Magikarp protection under its poisonous tentacles. The two are nearly inseparable until Magikarp evolves. The Magikarp of Aubir are still weak, but at least now they have a doting guardian.
After a few years living among poisonous tentacles, the Pokemon evolves and aquires an immunity to poison, and even produces its own poison within venom sacks at the base of its fangs. Although similar to its cousins in other regions, aubirian Gyarados is somewhat smaller and swims in a slithering motion, rather than an up and down undulation. This helps with hunting in the tight spaces of the reef. Gyarados has grown spikey and tough scales to guard against the bites of its rivals, and a long paddle like tail. It uses venom in its bite to quickly immobilize fish pokemon it preys on.
by Spuzzle91