How about koi, green dragon and blue carp?

Beautiful but extremely rare.

While traveling in Japan recently, a photographer named Dan Savage photographed an extremely rare blue koi carp in the carp pond of Maruoka Castle in Fukui Prefecture. Koi is an ornamental fish that is said to have originated in my country and was later introduced to Japan. Common koi colors include red, white, gold, black, etc., but blue carp are very rare. The fish also has some mottled red scales on its back, which seems to have gone through a discoloration process.