The untreated control test units exhibited total mortality within five
days; 97% of the total mortality occurred after day 3 (Figure I). Rapid
opercular movement, lethargy, and loss of equilibrium were noticed in many
fish prior to death in CuSO4-treated waters. At the end of the study, test
units that were treated with 1. I, 2.2, 3.3, and 4.4 mg/L CuSO4 exhibited
mortalities of 15.0, 81.7, 98.3, and 96.7%, respectively. The differences