Abstract: Acute toxicities of disinfectants and metal ions in varied concentrations on juvenile Murray cod, Maccullochella peelii peelii, was studied. The juvenile fish were tested for acute toxicity by the chemicals to provide crucial information for the aquaculture and diseases control. Solutions with a concentration gradient of copper sulfate, zinc sulfate, cadmium chloride, lead nitrate, chlorine dioxide, povidone-iodine, potassium permanganate, formaldehyde, and salt were prepared for the experiment. Using a hydrostatic method, the 24 h half lethal (LC₅₀), absolute lethal (LC₁₀₀) and safe (SC) concentrations of the disinfectants or metal ions on Murray cods were determined. The results showed SC for the fish on copper sulfate, zinc sulfate, chloride cadmium, lead nitrate, chlorine dioxide, povidone-iodine, potassium permanganate, formaldehyde, sodium chloride to be 0.122 3 mg·L^-1, 0.571 3 mg·L^-1, 0.020 0 mg·L^-1, 0.461 2 mg·L^-1, 5.030 0 mg·L^-1, 0.532 4 mg·L^-1, 0.958 9 mg·L^-1, 6.960 0 mg·L^-1, and 1.584 0 mg·L^-1. respectively. The severities of toxicity of the 4 metal ions and 5 disinfectants on the juvenile Murray cods ranked as:chloride cadmium > copper sulfate > zinc sulfate > povidone-iodine > potassium permanganate > chloride cadmium > sodium chloride > chlorine dioxide > formaldehyde.