Hi,
I live in Ashford Kent. I’ve got Koi and some goldfish ages fro 7yrs to 18yrs. In all those years I went from 1 gold fish in a bowl to 3 koi and a couple gold fish in a home made from decking and pvc liner 75gal pond on some slabs to my 11,000lt pond. In all that time we have only had a couple of problems until the hot weather which has changed everything.

Now one of the original 3 koi is poorly.