Chemical spills into water have recently raised concerns. The goal of this study was to examine the long-term toxicity of Tilapia guineensis, a widely used aquacultured fish, to sodium bromide, a frequently used disinfection agent. 96-hour lethal concentration (96h.LC50), median lethal time (MLT50), operculum beating rate (OBF), tail beating rate (TBF), and behavioral reactions to each. 150 T. guineensis were examined at various sodium bromide concentrations (0.00 mg/L control, 5.00, 10.00, 15, 00, and 20.00 mg/L). Their average length and weight were 15.99 and 145.77 cm, respectively. The findings demonstrated that T. guineensis exhibited early signs of stress, including increased opercula ventilation, erratic swimming, and gasping for air. Pattern of TBF response to time and concentrations. The cumulative fatality scores increased as exposure time and concentrations increased. These behavioral responses in aquatic creatures have been found to be sensitive markers of pollution levels. When utilizing sodium bromide-based herbicides near aquatic areas, caution should be exercised.