This study evaluated the impact of hairdressing salon effluents on the haematological parameters of Clarias gariepinus, a critical species for aquaculture and ecological balance. 75 Juvenile fish were exposed to increasing concentrations (10 ml, 20 ml, 30 ml, and 40 ml per 20 L) of the effluent for one week under controlled laboratory conditions. Haematological indices, including red blood cell count (RBC), haemoglobin (Hb), packed cell volume (PCV), and white blood cell count (WBC), were monitored. The results demonstrated significant dose dependent effects. At the highest effluent concentration (40 ml), RBC levels dropped to 2.94 ± 2.17 × 10⁶/µL compared to 4.49 ± 0.91 × 10⁶/µL in the control after a week of exposure. Similarly, Hb levels decreased to 8.35 ± 6.30 g/dL, compared to 12.97 ± 2.60 g/dL in the control and PCV declined to 25.33 ± 17.61% compared to 37.66 ± 6.65% in the control. WBC levels showed fluctuations without a clear dose-dependent trend, with the highest count observed at 10 mL (6.68 ± 1.31 × 10³/µL). Other indices such as MCV, MCH, MCHC, and differential counts showed minimal variation and were not significantly affected (P > 0.05). These changes indicate severe anaemia and impaired oxygen transport. These findings highlight the toxic effects of untreated salon effluents on freshwater ecosystems, demonstrating physiological stress and health deterioration in Clarias gariepinus. This underscores the need for effective waste management and regulatory frameworks to mitigate pollution from small-scale businesses.