Effect of Temperature Variation on the Growth Performance and Histopathological Activities in the Muscles of Freshwater Fish, Catla catla

This study investigates the impact of varying water temperatures (30°C, 33°C, and 36°C) on the growth performance and muscle tissue histopathology of Catla catla, an economically important Indian major carp. Over a 30-day period, specific growth rate (SGR), feed conversion ratio (FCR), and survival rate were measured to assess thermal effects on growth. The highest percentage of Dissolved Oxygen (DO) was recorded at 6.37±0.16 mg/ L on 10th and 30th days after treatment at 30oC, but no significant variation of pH level among all the experimental temperatures. The treated muscle tissues show different histopathological changes at the various temperatures. However, adaptive and degenerative changes were found to occur at the various temperatures of 33 and 36°C.Histopathological examination revealed mild muscle fiber shrinkage at 36°C, while fish maintained at 30–33°C exhibited optimal growth and normal muscle structure. These findings underscore the significance of temperature control in aquaculture systems to enhance growth performance and prevent physiological stress in cultured fish.