Shiny Majikarp and shiny Gyarados

In my iPhone while I was playing Pokémon GO, 

there was a shiny Magikarp and shiny Gyarados at the Gyms somewhere 

and I felt surprised. 

Shiny Magikarp is yellow and shiny Gyarados is red.
Shiny Magikarp and shiny Gyarados are different than 

the original Magikarp that is red 

and the original Gyarados that is blue.