Comparison of tank treatments with copper sulfate and potassium permanganate for sunshine bass with ichthyobodosis.

The biflagellated, single-celled parasite Ichthyobodo necator can cause significant losses among fish populations, particularly those cultured in tanks. Treatments of KMnO4 and CuSO4 were evaluated against a naturally occurring I. necator infestation on sunshine bass (female white bass Morone chrysops x male striped bass M. saxatilis) raised in tanks. Four-hour static treatments with 3 mg of KMnO4/L of water (2.5 mg/L above the determined KMnO4 demand) or 2 mg of CuSO4/L of water (total alkalinity = 207 mg/L; total hardness = 95 mg/L) were randomly applied to 4 tanks/treatment (23 fish/tank); the same treatments were reapplied 2 d later. Four tanks were used as positive controls. By 2 d posttreatment (after the second treatment), only 17.4% of the untreated control fish survived, and a sample of the remaining fish was heavily infested with I. necator. All remaining control fish were dead by 5 d posttreatment. The KMnO4 treatment significantly curtailed the initial mortality (survival = 92.4%) and slightly reduced the high parasite loads at 2 d posttreatment. However, fish mortalities increased dramatically over the next 3 d (survival at 5 d posttreatment = 37.5%), and parasite loads from sampled fish remained high. The CuSO4 treatment was effective in significantly lowering the parasite load (almost eliminating I. necator) and maintaining a high fish survival (87.5%) by 5 d posttreatment. The findings in this study clearly demonstrate that CuSO4 is a viable treatment for ichthyobodosis in tanks.