I am unsure whether it is a bug or it is intended to be like it but this is what I found; I was playing with axolotls on the Beta, breeding them and as soon as the baby popped out I scooped it up in a bucket. When I released it it turned blue (happened with a cyan baby and brown baby). I've read that they're rare and a small chance of being born as blue or even spawning as blue so this was relatively new to me but I would like to know if this is normal or something but overall I am enjoying the newly released features!