Iroage

Colour enhancement. Because Nishikigoi can not create the red pigments within their bodies it is necessary to feed foods with carotene to maintain the red colouration in Koi that have Hi plates. You can say 'the Koi needs Iroage' and it would mean that the Koi needs to increase its colour or that it should be fed colour-enhancing food.

(Courtesy of the excellent Book Kokugyo Vol II)