Simply Koi and More Koi

update, have seen these in the pond before on a koi - but now not so sure what they are?

either way they havent been killed by salt or fmg treatments?

here is a video:

https://youtu.be/wz6TaHzEYNg

Hi Guys, Looking for some advice before treatment on a costia outbreak on a 2k gallon pond. Starting to lose the will to live! Have tried all the usual, perhaps I have a strain of costia that is quite resilient? I have noticed My koi flashing every few minutes, water check Done and it's perfect acco...