Ichthyophthirius multifilis, also known as Ich or white spot disease, is probably the most well known aquatic parasite in the world. An Ich infestation is easily recognized by the tell tale white spots that appear all over a fish. The white spots look very similar to tiny salt granuals, peppered all over a Koi. The name for the white spots is Theront. When the Theront detaches and sinks to the bottom of a pond or tank, it is called a Trophont. The Trophont then seperates into hundreds of new parasites, which are called Tomites. The Tomites then look for a Koi attach to and repeat the life cycle. Ich, like any other parasite, can cause a secondary infection like Aeromonas.
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