Effect of copper sulphate on ichthyophthiriasis (white spot disease) in goldfish (Carassius auratus)

Abstract Goldfish ( Carassius auratus ) exposed to a CuSO 4 solution of 255 μ g Cu 2+ /l for 2 weeks and then transferred to copper-free water for 1 week, or exposed to a CuSO 4 solution of 288 μ g Cu 2+ /l for 2 h, showed 88.9% protection against Ichthyophthirius multifiliis as compared to 5.6% and 3.7% respectively in the control groups. The 24, 48, 72 and 96-h LC 50 values for copper sulphate in goldfish under local tap water conditions (pH 6.8–7.4 and hardness 72.5–80.3 mg CaCO 3 /l) were 365, 355, 301 and 288 μ g Cu 2+ /l as CuSO 4 ·5H 2 O respectively. The copper levels of fish tissue and tank water were also determined and its role in protection against I. multifiliis discussed.