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.