Researchers in the Red Sea have recently discovered that many different types of reef fish fluoresce red. Since red light is filtered out within the first 30 feet of reef water, it was believed that red was not a very relevant color in terms of fish vision. Using special light filtering goggles, divers were able to see that a wide variety of reef fish fluoresce red either as markings or as an overall glow. At least one of the images provided about this discovery clearly shows a common aquarium fish, the secretive wrasse, Pseudocheilinus evanidus. It would be interesting to find out the excitation and emission spectrum for this phenomenon to enable DIY solutions for viewing red fluorescence in our aquarium reef fish. Read more about this story at LiveScience. Image: Nico Michiels et al.