Bubble Eye Goldfish (Carassius auratus auratus)
Goldfish have been selectively bred for hundreds of years, resulting in a wide variation in morphology. The popular ornamental fish was first domesticated from wild carp in China, where orange mutations of the normally silver fish were recorded in the Jin Dynasty (265 - 420).
In the Tang dynasty (618 - 920), carp were commonly kept in ornamental ponds and were selectively bred for a gold mutation. By the Song Dynasty (920 - 1279), the domestication of goldfish was firmly established.
Today, there are about 300 distinct breeds recognised in China. Some popular varieties include features such as the bubble eye, telescope eyes, fancy tails and a compressed body. Many of these features provide significant disadvantage for the fish and as such, specialist care is needed to successfully raise and breed them.
Jordan Hartig on Wikimedia Commons