ABSTRACT Cultured European sea bass ( Dicentrarchus labrax ) and common carp ( Cyprinus carpio ) bones are crucial sources of fish collagen and can be used as a substitute for mammalian collagen. In this study, acid‐soluble collagen (ASC) were extracted from European sea bass ( Dicentrarchus labrax ; ASC‐S) and common carp ( Cyprinus carpio ; ASC‐C). Based on dry weight, collagen extracted from sea bass and common carp bones using acid treatments was 4.06% and 5.09%, respectively. Collagen extracted from common carp bones was higher than from sea bass bones ( p < 0.05). Glycine is the primary amino‐acid in both collagen, whereas proline, alanine, hydroxyproline, arginine and glutamic acid are all rather abundant. In addition, FTIR spectra revealed that the amide A, B, amide I, II, and III peaks of collagens were compatible and highly comparable with each other. According to research using SEM, both collagens have a fibrous structure and are porous. The collagen from the bones of sea bass and common carp was found to have a denaturation temperature of 32.17°C and 34.76°C, respectively, which is greater than that of the majority of other fish species. According to the findings of the X‐Ray Diffraction (XRD) examination, the two collagens kept their helical configurations. These findings suggest that a fish's living environment—whether it is freshwater or saltwater—has no direct impact on the qualities of its collagen, and that fish collagen may be used as a substitute for collagen derived from terrestrial animals in the food packaging, nutraceutical, and pharmaceutical sectors.