Juro, it is a fascinating topic for discussion with certainly many roads to follow. It also lends a great deal to our imagination, perception, and on the water visual experiences.
Let me cast this scenario on the waters of discussion. Suppose fish use the medium of water for sight, like humans use air to see. Water would seem invisible to them too. The impurities in the water like algae, and other suspended particles, make us believe they see it. But they really don't. What we see are actually effects not the causes. Striper's for example see about 50 feet in clear water. Why can't they see further under clear condition? Not because of clear water. Their eyes are design to focus in a peripheral direction like wide eye lenses thus making it difficult to focus on greater distances. Their hearing and smell senses take care of any long range situations.
As a fly tier/fisher, all we have to do at certain times is make a suggestion to a fish. When baitfish seem to blend into the environment, its not to make your fly color stand out, but make it visible by showing some sort of motion. Fish see effects (motion) when objects blend into the environment.
Like Juro stated about slower and more difficult fish conditions. Those are the more gratifying catches you remember.