Question

I tried it and all I got was standered magikarp.

Answer 1

Because breeding shiny pokemon does not make a shiny baby.

Matsuda Method:
Breed your Pokémon with Pokémon from another-language game. Increased chance to 4/8192

Normal:
As always, 1/8192

Answer 2

Yeah, breeding a Shiny pokemon does not make it a guarantee. The egg has the same chance of being shiny as it does with any other pokemon (about around 1/8000 chance) or something like that number.

Answer 3

Because When you breed a pokemon its just as likely to be a shiny as if you found a shiny in the wild (please edit thsat I don't know how to say that right) Unless its a japanese pokemon then its more likely