Sadly it has been confirmed by Mojang that they won't add the green axolotl that was shown in Minecon in-game, but why? That's because these are genetically modified and they don't exist naturally and only created by scientists, and the Minecraft team didn't like to add it, but why is there a blue axolotl? Because it has been popularized as a meme.

Notes:
You can't redistribute this mob skin in other websites.
If you want to use this mob skin, tell me for permission, if I say yes, you can, also, make sure to credit me properly on the credits.txt, like this:
Credits:
sadlittletree: https://www.planetminecraft.com/member/sadlittletree/