Just as humans cannot see air, fish cannot see water. This is because both air and water are transparent mediums that surround us. For fish, water is their natural environment, and their eyes have evolved to function optimally in this medium. They can see objects, colors, and movements within the water, but the water itself remains invisible to them.
Think of it like this: when you look through a clean glass window, you can see everything on the other side, but you don’t see the glass itself unless it’s dirty or reflecting light. Similarly, fish perceive their surroundings through the water, but the water itself is not something they can see.
In summary, fish do not see water in the same way that humans do not see air. Their vision is adapted to their environment, allowing them to navigate and survive effectively underwater.