I believe the term is 'Axanthic', as in missing the xanthin or the yellow pigment. I know there are populations of
Rana clamitans with this trait that are stable and healthy and the odd
Hyla cinerea seems to pop up on the web but I've never seen a blue Barking Treefrog.
Please breed it

. I'm not sure anyone bothers breeding Barkers for the pet industry, but it would probably be worth breeding blue ones and I know I'd love to have a few. I'd certainly love the chance to photograph a blue beauty like this.