Fishes are essential for mediating biogeochemical cycles in coastal areas by storing carbon (C), nitrogen (N), and phosphorus (P) in their body tissues at theoretically homeostatic rates. To maintain homeostasis, the consumers need to be in balance with their resource supply or alter their stoichiometric traits in response to environmental changes. However, the potential variations in the C:N:P content ratios of marine fishes are poorly understood. To explore the ecological stoichiometry characteristics of carbon (C), nitrogen (N) and phosphorus (P) in fishes from the Beibu Gulf, a total of 79 species (382 individuals) were collected and analyzed from 9 fishing ports around the study area from March to April, 2021. The results showed that the contents of C, N and P in fishes ranged from 33.87%-58.34%, 6.31%-14.92% and 0.77%-4.67%, respectively, and the variations ranges of C:N, C:P and N:P were 3.43-9.72, 19.15-173.06 and 5.04-33.68, respectively. The P content varied the most, resulting in variations in C:P and N:P in fishes, signifying that P content is an essential interspecies trait and an important factor in the diversification of the elementals composition of fish. The taxonomic level of fish families is the best predictor of ecological stoichiometry due to the significant differences among different families and little differences within families. Besides, the significant differences were found in C, N, and P contents, C:N, C:P and N:P among fishes with different body shapes and feeding habits (P<0.05). For instance, the ribbon-like form fish had the highest C content and the lowest P content, while the depressed form fish had the lowest C content and the highest P content; the omnivores had the lowest C content and the highest P content, which indicated that fish with higher C content had lower P content and vice versa. C:P and N:P of fish were significantly negatively correlated with P content (R²=0.966, P<0.01; R²=0.877, P<0.01). P content was significantly positively correlated with Ca content (R²=0.919, P<0.01) and its change might be related to the formation of fish bones and scales. Our results indicated that the fishes from the Beibu Gulf did not maintain strict homeostasis, and significant interspecies differences in the ecological stoichiometry characteristics of fishes were found due to their different body shapes and feeding habits. The research results are of great significance to the sustainable development of marine biogeochemical cycles and fishery resources under anthropogenic and environmental changes.