Fluorescent Fish

A new study points out that a good number of marine fish fluoresce red. (News source.)

"It has long been axiomatic that red light is simply not part of the mental universe of marine fish because the sunlight's longest visible wavelengths do not penetrate below a depth of ten metres (30 feet)." ...
"This foreshortening of the color spectrum under the waves was also assumed to correspond to a narrowed field of vision in fish, said the study's lead researcher in an interview." ...
"Looking through a filter while scuba diving that blocked out the brighter green and blue light waves, leaving only red ones, they suddenly saw a whole universe of sea creatures glowing various hues of cherry, crimson, ruby and rust."