Oh, selective breeding is very big in snakes. Just like with the fish, exact same concept. There are many species that have been bred for an exact colouration or pattern for over 20 years. And that is not even getting into genetic mutations, what are commonly called "morphs" in the herp community. But, that is a subject for another post.
And that little yellow one is tiny, almost as big around as a man's pinky. I'll get some pics with a size reference in them. He should work out to be deep green, with the red dorsal stripe turning blue.