1. Chromatophores: Fish have specialized cells called chromatophores that contain pigments, such as melanin, carotenoids, and pteridines. These pigments can be dispersed or concentrated within the chromatophores, allowing the fish to change its color.
2. Reflectors: Some fish have reflective cells called iridophores that scatter light and create iridescent colors. The angle of the light hitting the iridophores can change the color that is reflected, allowing the fish to change its appearance.
3. Structural changes: Some fish can change colors by altering the structure of their skin, such as by raising or lowering ridges or scales. This can create different patterns and colors on the fish's body.
4. Hormonal control: The release of hormones can influence the activity and distribution of chromatophores and iridophores, allowing the fish to change colors in response to environmental cues, such as light intensity, temperature, or social interactions.
5. Camouflage: Many fish use color changes to camouflage themselves from predators or prey. By matching their surroundings, they can avoid detection and increase their chances of survival.
6. Communication: Some fish use color changes to communicate with each other. For example, some species of damselfish change colors during mating rituals or to establish dominance over other fish.