author(s)
Rashmi Prabha Mishra, Navin Kumar, Jyoti Prabha Mishra, Nihar Ranjan Sarangi and Chandra Kanta Mishra

abstract
The acute toxicity of KMnO4 to various fish species has been studied. A limited amount of information is available about the toxicity of KMnO4. However, there are very scanty or no data for stinging cat fish species. The present study was undertaken to ascertain the changes in hydrological parameters as well as the lethal toxicity effect on Heteropneustes fossilis fingerlings with response to Potassium Permanganate (PP) after every one hour of exposure period. Live and healthy fingerlings of Heteroneustes fossilis (mean weight, 3.7±1.30 g and mean length, 7.32±1.53 cm) and rohu, Labeo rohita (mean weight, 5.5±0.88 g and mean length, 5.36±1.0 cm) of either sex were procured from local fish market located at Naihati of West Bengal, India. They were transported in separate oxygenated polythene bags to the laboratory for experiment and were maintained in the laboratory for a minimum period of 14 days & fed with commercial pelleted feed of size 2 mm. Approximately 20 % of Water exchange was done on daily basis. Mortality during the period of acclimatization was observed which is less than two percent. The toxicity bioassays of Potassium Permanganate was conducted separately for 2h, 3h, and 4 h of exposures to the fingerlings of Heteropneustes fossilis in controlled laboratory conditions following the methods of APHA (2002) to get the 100% mortality of the test fish. Lethal Concentrations of this toxicant at which the test organisms died (LC₅ to LC₉₅) calculated by the method of Probit Analysis (Finney, 1971).Impacts of Potassium Permanganate on different hydrological parameters like Temperature, pH, Conductivity and Dissolved oxygen of test water were assessed following the methods of (APHA, 2002) during this Experiment. Data generated from the estimation of water quality parameters were analyzed statistically following the methods of (Gomez and Gomez, 1984) using Statistical Software’s (SPSS and MS Excel). Effects of Potassium Permanganate on Hydrological Parameters were also observed. In the present investigation, the role of the KMnO₄ as piscicides was evaluated. It was observed that about 95% hardy fingerlings of Heteropneustes fossilis could be removed at the concentration of only 20-25mg/l KMnO₄ only for 4h. From the analysis it was found out that the lethal dose of KMnO₄ is comparatively very high. In addition, the toxic effect of KMnO₄ retains up to several days. Therefore, it should not be recommended as an ideal Piscicide. However, it is strongly encouraged to use KMnO₄ as disinfectant, therapeutants and prophylactic.