Koi Forum • Algae growing on fish!! what to do? : Koi Health

Hi all, been looking round the forum for a while but never needed to post untill now.

I have a 6000 litre pond with a cloverleaf 4 chamber filter and UV clarifier. everything is great except one of my Blue Orf has started turning green with what looks like Algae, none of the other fish are affected.

What should I do with it??