Jewel Cichlid is one of the most beautiful an‎d popular species of ornamental fish, native to Africa. According to previous studies, water temperature is considered a key an‎d influential factor in fish growth, with increased temperature often leading to a higher metabolic rate an‎d accelerated chemical rea ctions. The present study aims to investigate the effects of different temperatures on growth an‎d developmental indices an‎d to conduct a histopathological eva‎luation of gill tissue. In this research, 75 juvenile Jewel Cichlid fish with an average weight of 0.64 ± 0.18 g an‎d a length of 2.86 ± 0.38 cm were reared in three 50-liter aquariums, with a density of 2 fish per liter, under three temperature groups: 26 °C, 30 °C, an‎d 35 °C, over a period of 16 weeks. At the end of the rearing period, growth eva‎luations indicated that the average final weight an‎d length were highest in the 30 °C tr, followed by the 26 °C group, while the 35 °C group showed the lowest growth. Additionally, the survival rate was 100% in the 26 °C an‎d 30 °C groups, whereas the 35 °C group had the lowest survival rate at 93%. Histological observations revealed that at 26 °C, gill tissue structure was in better condition, with no signs of the examined damage. In the 30 °C group, mild necrosis, shortening, curling, an‎d twisting of secondary gill lamellae were observed. With further temperature increase to 35 °C, more severe changes occurred, including severe necrosis, hypertrophy, shrinkage, an‎d dilation of gill filaments. Overall, the findings suggest that the optimal rearing temperature for this species is 30 °C.

فاطمه پيكان حيرتي , يزدان كيواني

سالار درافشان , اميرحسين جلالي حاجي آبادي