Fish See in Color
 Q: I'm doing a science fair project about fish
and have two questions: one, do they see in
color, and two do they have a color
preference? --B.R.
A: Most fish see in color. "Experimental evidence
indicates that many shallow-water fishes, if not
all, have color vision and see some colors
especially well," says the Encyclopedia
Britannica, "but some bottom-dwelling shore
fishes live in areas where the water is sufficiently
deep to filter out most, if not all, colors." These
bottom dwellers do not respond to color differences when tested in shallow waters.
"Red is a common color in fish," says the National Aquarium in Baltimore. Perhaps that's the
color they prefer. If so, they have for a long time. A 370-million-year-old fish fossil sports red and
silver coloration, reports the Proceedings of the Royal Society. Seeing in color has helped animals
survive through the ages.
Fish may choose red, through an evolutionary process, to elude predators. Red fish live in dark
waters. Water absorbs light energy, the longest wavelengths go first: red, followed by orange,
yellow, green, blue, indigo, and violet. Thus red is good camouflage. In deep water or at night,
red appears gray.
Figure: Hawaiian Squirrelfish, the Island's most abundant squirrelfish, is nocturnal. It spends
daylight hours in caves and emerges at night to forage among coral reefs for prey. (Courtesy of
Richard L. Pyle, Bishop's Museum, Hawaii)
Further Surfing:
Color Vision, Computational Neurobiology Lab of the Salk Institute for Biological Studies in La
Jolla, California.
"How to select lure colors for successful fishing", University of Wisconsin
"Fish Biology and Anatomy", National Aquarium in Baltimore,
Ichthyology, Bishop's Museum--Natural Sciences Department: Fish databases and beautiful
images.
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