NO, acute toxicity evaluation of a disinfectant containing tetraacetylethylenediamine (TAED): The acute toxicity of a disinfectant consisting of percarbonate and TAED was assessed by measuring the behavioural response of aquatic organisms (e.g., medaka and zebrafish) when exposed to the disinfectant, as well as the lethal concentration. The results showed that the LC50 of the disinfectant to fish was 135.76 ppm and that the LC50 of the disinfectant may be influenced by the pH of the water exposed to the disinfectant rather than by the dissolved oxygen in the water. In addition, the results of image analysis indicated that the behavioural response of fish could be further evaluated for the acute toxicity of the disinfectant at concentrations below the LC50 and that a relationship (R2= 0.85) existed between behavioural response and fish survival.