UV Vision in Fish: Match the Ultra-Violet-Hatch (Article 1 of 2)
Many animals, including many fish, have Tetra-chromatic color vision. This means they have four, not three, primary color cones. Tetra-chromatic color vision, having four primary color cones, requires a combination of four primary colors within an object before the object is the color white (i.e. seen as being white). In other words, four primary colors comprise the color white, not three like with humans. Any clue what the forth color is? Hint: This article is about UV vision.