Trichodina can be found in fresh water and marine systems. They are ciliated protozoans which tend to cause problems especially if there are water quality issues. They can inhabit both the gills and the skin of fish, and cause increased mucus secretion as well as irritation.

Their life cycle is simple – they divide by binary fission, and their optimum conditions for reproduction are the same as the fish they infest.

While small numbers of these organisms on a fish generally do not cause much of a health problem, large numbers can cause moderate to serious pathology and ultimately, death of fish. Small fish and fry are especially susceptible, and mortality can occur quickly if undiagnosed.

Diagnosis is by microscopic examination of skin or gill scrapes to see the characteristic flattened round or oval structure with a ‘tooth – like’ internal ring.


Trichodina can be treated by the administration of Fluke-Solve™ at the recommended dose – field trials on standard back garden ponds have confirmed this at least greatly reduces their numbers, and in a number of cases has completely eliminated them from the pond.