What Is Karasu Koi?

Karasu Koi, also known as the Black Koi or Magoi Koi, is a popular and highly valued variety of koi fish. This unique type of koi has a striking black coloration that sets it apart from other koi varieties. In this article, we will explore the origins, characteristics, and care requirements of Karasu Koi.

Origins of Karasu Koi

Karasu Koi is believed to have originated in Japan during the early 19th century. The name “Karasu” means “crow” in Japanese, which refers to the fish’s dark black coloration.

Karasu Koi was initially bred from wild carp known as Magoi. Over time, breeders have refined and improved this variety through selective breeding.

Characteristics of Karasu Koi

One of the most distinctive features of Karasu Koi is its deep black coloration. This shade is not simply a uniform black but rather a rich and layered hue that can range from jet black to charcoal grey. The scales on its body are usually large and thick, giving it a rugged appearance.

In terms of size, Karasu Koi can grow up to 36 inches in length and can weigh up to 25 pounds. It is an omnivorous fish that feeds on a variety of foods such as pellets, insects, worms, and algae.

Care Requirements for Karasu Koi

To keep your Karasu Koi healthy and happy, you need to provide them with proper care. This includes maintaining their water quality by regularly testing for pH levels, ammonia levels, and nitrite levels. They also require ample space in their pond or tank as they can grow quite large.

Feeding your Karasu Koi with high-quality food is crucial for their health and well-being. You can feed them with commercial koi pellets or supplement their diet with live foods such as bloodworms, brine shrimp, and daphnia.


In conclusion, Karasu Koi is a stunning and highly sought-after variety of koi fish. Its deep black coloration and rugged appearance make it a unique addition to any pond or aquarium. With proper care and attention, your Karasu Koi can thrive and live for many years to come.

Photo of author

Emma Gibson