Fish scales contain collagen. Fish Collagen: The Answer to Smoother Skin. … It, combined with hyaluronic acid and elastin within the extracellular matrix, give the skin its structure, elasticity and firmness, and overall health and longevity. Therefore, collagen is a critical building block of the skin. In addition, fish scales contain chitin, organic material that can be transformed into chitosan. Chitosan has multiple applications for biomedicine, dietary supplements and agriculture, etc.