What color is the most conspicuous underwater?

Underwater, dark and fluorescent colors are the most conspicuous.

In underwater environment, dark and fluorescent colors are often the most conspicuous colors. Fluorescent color has high contrast and saturation in water and is relatively easy to be noticed in water. Dark colors such as purple and black can also be seen clearly in water, because they are in sharp contrast with the background of water. In the outdoor environment, dark colors are not recommended, because dark colors can be mistaken for natural elements such as soil, leaves or shadows. In outdoor activities, choosing bright colors can better contrast with the natural environment and improve visibility and safety.