Ichthyophthirius, more commonly known as white spot or Ich. White spot can be difficult to treat due to its life cycle can be difficult to treat. White spot cysts, appear as small white nodules on the skin, gills and fins, in advanced outbreaks these can be seen by the naked eye appearing like grains of salt. In a confirmatory skin scrape the trophonts appear as dark round objects slowly rolling around.

Treatment
Treatment is only possible in the free-swimming infective stage. In order to reproduce the adult detachs itself from its host fish. It swims around in the water, and attaches itself to an inanimate substrate (plants, bottom of the pond, or stones), after which it transforms into a cyst. It then devides into about 2000 daughter cells, which swim around looking for a host fish. The speed at which this process takes place is temperature related and thus treatment should be as follows.

White Spot should be treated with a combination of Formaldehyde and Malachite, treat 3 times, or Parazoryne

At 25 Celcius tretment should be repeated after 4 days.

At 18 Celcius treatment should be repeated after 6 days

At 10 Celcius treatment should be repeated after 10 days.