One fish, two fish, glowing red fish
It looks like Dr. Seuss got it right when he rhymed "One fish, two fish, red fish, blue fish."
Scientists have discovered, contrary to what was previously thought, red is a favorite color among fish and many are even capable of glowing red.
It had been concluded that because red wavelengths are absorbed below 10m - objects which look red under normal conditions appear grey or black after 10m - red colours are of no importance to fish.
But now boffins have found at least 32 reef fish species that fluoresced (glow) visibly in red, and not just when they are angry.
Because the light is coming from the fish themselves and not filtering down from the surface, the red glow remains visible at depth and is easily seen at close distances.
Nico Michiels, from the University of Tübingen, Germany, said: "We believe red fluorescence may be part of a private communication system in fish.
"Red fluorescence is at the borderline of what is visible to many marine fish, and due to rapid attenuation of red light by water, even those that can see red will be able to see it over short distances only.
"Fluorescent eye rings may function as an indicator of presence or reveal the direction of gaze."
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