Infected ponds, tanks, or raceweays will become Ich-free if left without any fish for a period of 7 days with water temperature at least 68 F. New fish should be quarantined for at least one week at 70 F for warmwater species and two weeks at 60 F for coldwater species. Such a quarantine will allow the disease to manifest itself prior to being introduced to healthy fish. Even with these precautions outbreaks of Ich may still occur. As a result, two categories of treatments, chemical and mechanical, will be discussed. Chemical Treatment of Ich with chemicals can be costly and time-consuming.
Copper sulfate is used at whatever concentration is safe in the existing water chemistry.
Copper ions are extremely toxic to fish and the degree of toxicity depends on the water hardness. Treat on alternate days, with two to four applications necessary. Regardless of water hardness, treatments should be reduced by one-half during the third and fourth treatment. The use of formalin in large ponds is effective but can be cost prohibitive. Two to four applications, made on alternate days, should be used, with the higher dosage being the most effective.