Prognosis
When Ich is diagnosed early, effective treatment is used, and stresses are minimised, mortality rates can be low. However, if the infection is at an advanced stage, treatment protocols are not followed, and the fish are stressed, higher death rates will occur. When a fish has had Ich eradicated, it may develop partial resistance to reinfection. Partially treated fish may initially harbour low numbers of unseen trophozoites, often in the gills. This subclinical carrier will cause another outbreak weeks later, most likely when stresses occur or uninfected fish are introduced to the aquarium.
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