This is a doitsu koi with a 'killer whale' pattern (a black body with white markings).
The term 'kumonryu' means 'nine-crested dragon." in Japanese. Kumonryu koi are unique in the sense that their sumi is unstable, allowing them to change their black-and-white patterns even after they have matured. They are therefore also known as the Chameleon of koi.
They are also decribed by some as 'forever tategoi.' because the change all the time, and ugly ducklings can turn into swan's in a short period of time.
The kumonryu is a relatively new koi variety, acquiring a category of its own in the All Japan show only in 1994.
There is also a beni Kumonryu version with red markings.