The advantages of fish meals for human nutrition and health have recently attracted considerable attention. Throughout the past few decades, their consumption has significantly increased due to their excellent nutritional content. Both the rohu (Labeo rohita) and mori (Cirrhinus mrigala), which are Pakistan commercial fish species, are significant aquatic food sources. The purpose of this study was to determine how sodium acetate and a particular natural preservative, black cumin (Nigella sativa), affected the protein and fat content of L. rohita and C. mrigala. We bought 96 species samples, cleaned them, and removed the guts. Six of the 96 samples were freshly examined, with the remaining samples serving as the experimental and control groups. The control group was without preservatives, and both species were preserved in the experimental group with black cumin and sodium acetate at concentrations of (3g/l, 5g/l, and 7g/l). Samples of both species were frozen at 4±1ºC for 15, 30 and 45 days. In the fresh sample of L. rohita, the highest % value of protein 30.382±1.835 was observed, while black cumin seed oil showed values from 28.437±1.546 to 24.791±1.263 and sodium acetate quantified the highest % value at 26.916±2.162 and the lowest % value at 19.687±2.177. In C. mrigala on the first day, the peak of protein was 28.437±1.786, black cumin seed oil indicated values from 27.708±1.262 to 21.729±2.409 and sodium acetate showed the maximum value at 26.979±1.262 and the least value at 21.145±1.263. While the % value of fat in the fresh sample of L. rohita on the first day was 11.67±0.235 with black cumin seed oil it ranged from 10.83±0.288 to 8.33±0.577 and sodium acetate indicated values from 10.66±0.288 to 7.66±0.763. In C. mrigala, the fresh sample had 12.67±0.288% fat content. Black cumin seed oil represented % values from 12.83±0.288 to 10.17±0.763 and sodium acetate ranged from 12±0.866 to 8.83±0.763. The results explained that when compared with the experimental group, the maximum % value was observed on the 15th day and the minimum on the 45th day.