The chemical analysis of Sargassum aquifolium and Padina boergesenii macro-algae were determined besides evaluating their impact on fish water quality. Fresh algal samples were collected from the National Institute of Oceanography and Fisheries in Egypt during winter-spring. Moisture, total protein, lipids, carbohydrates, fibers, and ash levels were determined. The effect of macro-algae on the water quality of a high ammonia content solution was studied in triplicate with three treatments utilizing seawater containing ammonia of 0.428 ppm and the algae were added daily for successive days: The first treatment was supplied with 0.25 g of the dried S. aquifolium per day, the second treatment was supplied with 0.25 g P. boergesenii per day, and the third tank served as a control. Regarding the influence of macro-algae on NH₃ concentration, the S aquifolium group demonstrated the lowest significant value on the first day, followed by P. boergesenii. There was a significant negative correlation between NH₄ and salinity, and a positive correlation between NH₃ and NH₄, with all treatments showing a clear correlation between NH₃ and pH, providing valuable insights into the potential impacts of algae on fish habitats.