Difference Between Koi and Goldfish

Koi vs Goldfish
Koi and goldfish have more similarities than differences. For starters, they are both members of the cyprinidae, or carp family of fish. In fact, they are so closely related that they are able to breed with each other, though their offspring will be sterile. Immature koi and goldfish can often be mistaken for each other. The differences between koi and goldfish lie in their history, breeding, and physical characteristics.

History
Koi are common carp. In Japan in the 1820’s, they began to be selectively bred.
Goldfish are also a variety Asian carp. The first recorded selective breeding of goldfish took place in China during the Jin Dynasty (265-420AD).

Breeding
Koi are bred for their patterns, colors, and scalation. The most common colors are black, white, yellow, red, cream, and blue. New varieties of koi are still being developed. However, because koi are less than 300 years into their selective breeding they will revert to their natural grayish color within a couple of generations if released into the wild.
Goldfish were initially bred for their yellow or orange color in the ponds of Chinese elite. Nowadays most goldfish are a bright orange color and are bred for their body shape. There is a great variety of fin and tail shapes in goldfish as well.

Physical Characteristics
Koi have the streamlined shape of common carp. The best way to tell the difference between immature koi and goldfish is by looking for barbels. Barbels are small whisker-like sensory organs that hang by the koi’s mouth. Goldfish do not have barbels. Koi generally grow to be around 24 inches in length, however some koi have been known to reach over a meter. Koi are also very long-lived. When in a well-kept outdoor pond they can easily reach 100 years. The oldest koi on record lived 226 years.
Goldfish have varied shapes, depending on their breeding. Generally, goldfish have flowing tails and fins and a slightly pudgy body. Some have puffy ‘cheeks,’ or lumps on the tops of their heads. They generally reach a size of approximately 10 inches, but this determined by the size of their bowl. In optimal conditions goldfish can live past 20 years, but most household pets rarely reach 10 years.

Summary
1.Koi were first bred in the 1820’s in Japan while goldfish were first bred in  300AD in China.
2.Koi are bred for their colors and patterns; but goldfish are bred for body shape and color.
3.Koi are larger and live longer than goldfish.
4.Koi look like carp except for their coloration while goldfish have elaborate body shapes.

Complete guides for KOI and Goldfish care.

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