Investigating the impact of external application of formalin and potassium permanganate on hematological, immunological, and biochemical profiles in fingerlings.

The present study aimed to elucidate the suitability of formalin and KMnO as therapeutics for fish diseases in Indian major carp, , while considering their impact on fish stress levels. Acute toxicity tests revealed that the 96-hour LC values for formalin and KMnO were 66.58 ppm and 2.89 ppm, respectively. Sub-lethal concentrations of formalin (6.65 ppm, 3.32 ppm, and 2.21 ppm) and KMnO (0.289 ppm, 0.145 ppm, and 0.096 ppm), along with control groups, were administered to the fish for different exposure periods (24, 48, 72, and 96 hours) and different hematological, biochemical, and immunological parameters were analyzed. The findings demonstrated that formalin exposure resulted in a significant decrease ( < 0.05) in hematological parameters, immunological parameters, and serum protein levels. Conversely, formalin exposure led to significant increases ( < 0.05) in serum glucose, SGOT, SGPT, and ALP levels. In contrast, KMnO exposure significantly decreased ( < 0.05) hematological parameters and serum protein levels, while significantly increasing ( < 0.05) immunological parameters. To evaluate curative efficacy, challenge studies were conducted using three sub-lethal concentrations of formalin and KMnO against (ATCC 7966) infection. Based on the aforementioned results, the recommended doses of formalin and KMnO were found to be 6.65 ppm and 0.289 ppm, respectively.