The Goldfish Variations

From bubble eyes to lionheads, selective breeding has produced an amazing array of goldfish forms.

In the lauded library of Bach's piano music, the Goldberg Variations stand apart as one of the finest examples of development and variation in musical history. In the realm of selective breeding, it may be goldfish that deserve this distinction. Over the past ten centuries, humans have been selecting unusual goldfish and breeding them to achieve desired traits, including multiple or modified fins, striking color combinations, and bizarre growths around the head.

The first "fancy" goldfish appeared firmly in recorded history during China's Sung Dynasty (960-1279 AD). Since then, the fish and the breeding techniques used to create them have spread, finally making their way to the United States in the 1850's. Across time and geographic borders, a wide range of goldfish variations have been bred, but despite vastly different appearances, they all still belong to the same species as their Asian ancestors - Carassius auratus.

With their selection powered by humans instead of nature, not all goldfish variations would survive in the wild. Ogling the outside world with marble-sized, fluid-filled eye sacs, bubble eyes have a tendency to blind themselves by swimming into unseen obstacles. Lionheads have vision problems for a different reason - the puffy nodules that grow around their heads often envelop their eyes and gills.

Ogling the outside world with marble-sized, fluid-filled eye sacs, bubble eyes have a tendency to blind themselves by swimming into unseen obstacles.

 

For fancy breeds such as the black moor and the lionhead, the term goldfish can take on a literal meaning - these fish can sell for over $5,000.
Photo: John H. Tashjian, CAS Library Special Collection