I believe he is also $599.00...but the owner wife doesn't want to sell him. She loves him LOL, I think he has lowered the price to $549.00. He is a stunning bright yellow though...very beautiful fish.
My Puffers: Puffers I have kept: T lineatus T miurus A modestus T biocellatus C valentini C coranata C papuan C lorteti DPs suvattii burrfish T niphobles
This likely is no transition in the color morphs. Most yellow color morphs have small parts of standard A. meleagris color. But they are like this from birth and stay like this all their lives.
The color condition is somewhat similar to albinism, it's called xanthism (Xanthochromism, Xanthorism can also be used) and occurs in a number of fishes. A fish with very similar color morphs as A. meleagris is the moray G. miliaris, of which the yellow morph is traded as "Banana eel" or "Atlantic golden moray".
Give a man a fish, and he'll eat for a day. Give a fish a man, and he'll eat for weeks.