Chilodonella can be identified by the small hair (cilia) on the body, especially on the longer side and can only be identified with a microscope.
It can swim, using the cilia, and can therefore attach to your nets and filters.
They attach themselves to the koi, causing irritation.
Your koi will probably hang at the bottom, separate themselves from the other, and the fins will be clamped against the body. It will also probably flick or rub themselves against the bottom or sides of the pond, causing secondary damage. They will also loose their appetite.
They normally cause havoc during winter when the water is very cold, and very seldom cause problems during warm summer periods.
The best treatment is a combination of Malachite green and Formalin(FMC) if you do not have a lot of salt in your water. (Up to 0.2 is fine)
If you do have salt in your water, increase the salt concentration to at least 4kg/1000 liters and/or treat with potassium permanganate at 2 grams per 1000 liters.
A mpeg video of Chilodonella can be downloaded and viewed from our website.(360 kb) Click here to view: http://www.koionline.co.za/chilodonella.mpeg