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 KMnO 4 and CuSO 4 were evaluated against a naturally occurring I. necator infestation on sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis ) raised in tanks. Four‐hour static treatments with 3 mg of KMnO 4 /L of water (2.5 mg/L above the determined KMnO 4 demand) or 2 mg of CuSO 4 /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 KMnO 4 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 CuSO 4 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 CuSO 4 is a viable treatment for ichthyobodosis in tanks.