Vol. 8, Issue 4, Part i (2024)

Abstract: The chronic or sub-lethal toxicity test was performed on fish, Labeo rohita (weight 5.05±0.02g, length 7±0.03 cm) with thirteen different pH values such as 4.5, 5, 7 (Control), 9.5 and 10. Fish were fed pelleted feed with 35% crude protein. The alanine-amino-transferase (ALT) activities were lower at pH 4.5 and pH 10, and higher at pH 9.5. While Aspartate-amino-Transferase (AST) activities were lower at pH 4.5 and pH 5, and higher at pH 7 (control). The ALT activity recovered after 14 days recovery test in tap water (pH 8.2) of the fish group exposed to pH 9.5. While no AST activity recovery observed. Dissolved oxygen (DO) was highest and there was no ammonia-nitrogen (NH₃-N) at pH 7 (control). While the alkalinity contents in water were highest at basic pH 9.5 and pH 10.