It is a Tancho Oyo! Oyo (Japanese word which means 'yellow leaves' when leaves turn color in autumn) came out from a cross between Goshiki and Ochiba-sigure.
Oyo carries a hue of color very similar to that of Ochiba-sigure, but in more light orange-yellow color. This is a new variety yet, and the biggest now are only Sansais (3yr-old), when this variety becomes more popular and become available in bigger sizes, they would be a bright addition to your pond.
South African Koi Industry