author(s)
Dina Nath Pandit and Amrita Jaiswal

abstract
A maiden study was conducted to evaluate the acute toxicity and ethological stress of chloramphenicol and ginger to an Indian freshwater air-breathing fish Channa punctatus (Bloch). 96hr-LC₅₀ dose of fish was determined by Behrens-Karber and Reed-Muench method. The safety levels of these materials were calculated by various methods. The physico-chemical parameters of experimental were found with the favourable limits. The ideal median 96hr-LC₅₀ value was determined 55.14 mg L^-1 and 3251.25 mg fish^-1 (56.5g kg^-1) for chloramphenicol and ginger respectively in a semi-static method. The observations indicated that the fish were more sensitive to chloramphenicol than ginger. There were large variations in the safe levels estimated by different methods for the test materials. In addition to dose and dose-time dependent increase in mortality rate, stress signs in the form of behavioral changes were observed in response to the test materials. Therefore, precautions should be taken when high concentrations of chloramphenicol and ginger are used in chronic treatment of Channa punctatus.