Koi Health- How can I stop koi colours fading?

Koi cannot produce the colours themselves and need carotenoids( colourants) in their diet to help produce the colour. Hikari Gold and Saki Colour both contain Astaxanthin, a powerful colour enhancer, which will brighten up the orange/ red on your koi without affecting the whites. Poorer quality foods may make the whites appear creamy. Feed above 16C for best results.