Unless specifically stated most of these problems can be treated using commercial remedies which state what they are for on the packaging, ask dealer for advice if you don't know which one to buy. Sliminess of the skin . A greyish white film of excess mucus on the body. This is a reaction to protozoan parasites, notably Ichthyobodo , Trichodina and Chilodonella . Other symptoms of infection by these parasites are scratching and leaping followed by lethargy and failure to eat.
Further risks are secondary bacterial and fungal infections of wounds caused by scratching.
The parasites are particularly active in spring when koi are still recovering from winter. Caused by Ichthyopthirius multifiliis . The white spots on the skin, gills and fins are individual protozoan cells that are under the skin and feed on the body fluids and cells. They then punch out of the skin and fall to the bottom of the pond, collect together and begin breeding, the offspring then reinfest the fish. As well as white spots symptoms are scratching and swimming into the water inlet, failure to feed and lethargy.