White Blobs on Koi?
Koi Carp Pox
White or pink waxy blobs can often appear on koi, both on the body and the fins. This is perfectly harmless and is commonly known as CARP POX.
Think of them as similar to a human cold sore, or a wart. They are viral, so no attempt should be made to remove them, otherwise they will release the virus into the pond and infect other fish.
The fish are in no danger if they have carp pox and it generally disappears as the water temperatures increase.
So, if your koi have white waxy blobs, leave them alone, they will disappear eventually!