From Science.gov research search: Japanese koi fish:  "Complete mitochondrial genome (mitogenome) sequences were determined for two individuals of Japanese ornamental koi carp. Interestingly, the obtained mitogenomes (16,581 bp) were both completely identical to the recently reported mitogenome of Oujiang color carp from China. Control region (CR) sequences in DNA database demonstrated that more than half (65%) of the koi carp individuals so far reported had partial or complete CR sequences identical to those from Oujiang color carp. These results might suggest that the Japanese koi carp has been originated from Chinese Oujiang color carp, contrary to the belief in Japan that the koi carps have been developed directly from carp stocks in Japan. In any case, the present results emphasize the importance of analyzing Oujiang color carp when studying the origin of koi carp."
 
"The complete mitochondrial genome of the koi carp (Cyprinus carpio, Cyprinidae) was sequenced in the present study by using Ion Torrent Personal Genome Machine (PGM) platform for the first time. The mitochondrial genome sequence is 16 581 bp in size and consists of 13 protein-coding genes, 22 tRNA genes, two rRNA genes and one control region. The gene order and organization were similar to most of the other teleost. "
 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7800863/ (for article)