Distinctive fish with a surprising story.
Koi come in a large variety of colours and patterns. Black koi are set apart by their colouring, but share the same long-lived, captivating nature as other varieties. Many koi live around 25 to 35 years with good care.
Breeding and early development
Male koi can often be recognised by their concave anal section and may show breeding spots on the head. A spawning can produce up to 1,000 eggs. The young fish, known as fry, begin emerging in around four to seven days depending on water temperature.
Their distinctive colour does not usually emerge until fry are between three and twelve weeks old. Japanese breeders developed koi from carp mutations; intensive breeding created the many combinations seen today.
Size and the Magoi
Black koi can grow to around 36 inches, so they need a large pond. The Magoi is one of the earliest all-black mutations and can grow very large. It is deep bronze, but appears black when viewed from above. Magoi blood has been introduced into other varieties to encourage strong growth potential.
Karasu: the crow koi
The Karasu, meaning “crow” in Japanese, is an extremely old species with black fins and a black body. Some Karasu show a white or orange belly.
Koi that change colour
Koi may change colour in response to their environment or diet. The Matsukawabake takes this ability further: it commonly has white areas and may turn completely black or white depending on water temperature or season, before returning to its original pattern.
The Kumonryu
The Kumonryu, meaning “dragon fish”, is one of the most popular black koi varieties. Its pattern has been compared to dragons in ancient paintings or dragons rising through white clouds. Like the Matsukawabake, it can also change colour.
The huge range of koi colours is one of their great attractions. With certain black koi varieties, that beauty can literally change before your eyes.