Tancho
A variant of Koi (Cyprinus rubrofuscus)

Photo: Immanuel Giel · CC0
Named for the head marking: a single red circle on the head, with no red elsewhere on the body.
A variant of Koi (Cyprinus rubrofuscus)

Photo: Immanuel Giel · CC0
Named for the head marking: a single red circle on the head, with no red elsewhere on the body.