1. Guanine Crystals:
* The primary reason for the silvery sheen is the presence of guanine crystals in the scales.
* Guaning is a chemical compound found naturally in many organisms.
* These crystals are stacked in a layered structure within the scales, acting like tiny mirrors.
2. Reflection of Light:
* When light hits the guanine crystals, it reflects off the layers.
* This reflection is strongest for wavelengths of light in the blue-green range, which is why fish often appear silvery or iridescent.
3. Camouflage and Protection:
* This silvery coloration serves a vital purpose: camouflage.
* In the water, sunlight is often scattered, and the silvery scales help fish blend in with the surrounding environment, making it harder for predators to spot them.
* Additionally, the reflection of light can also confuse predators, making it difficult for them to target the fish.
4. Not All Fish are Silver:
* It's important to remember that not all fish are silver.
* Many species have different colors for various reasons, such as attracting mates, warning predators, or blending into specific environments.
So, the silvery appearance of many fish scales is mainly due to the presence of guanine crystals that reflect light effectively. This coloration provides camouflage and protection, enhancing their survival in the aquatic world.