The Problem of Bright-colored Fishes 



Bv JOHN TREADWELL NICHOLS 



THE colors of the majority of north- 

 ern fishes are rather dull. Many 

 species found about tropical reefs, 

 on the other hand, are very highly 

 colored, with bold or bizarre markings. 

 The Bermudas, and Santa Catalina 

 Island in California, are famous for such 

 brightly colored fishes, and tourists 

 admire them at these places from spe- 

 cially constructed glass-bottomed boats. 

 Looking through the glass, vision is not 

 hampered by the glare of the ruffled 

 surface, and one can look down through 

 the limpid oceanic water to where the 

 fishes ply in and out among the pictur- 

 esque heads of coral and other forms of 

 fixed marine life at the bottom. Living 

 fishes of bright color have been very 

 successfully installed by the New York 

 Aquarium, in tanks where they are 

 admired by crowds of people who other- 

 wise would not have the opportunity 

 to enjoy them. Quite apart from their 

 popvilar interest, the gaudy colors of 

 such fishes have long appealed to the 

 naturalist; they have been the subject 

 of considerable serious study, and vari- 

 ous theories have been advanced to 

 explain them. 



Wallace claimed that their bright 

 colors matched the brilliant corals and 

 seaweeds of the reef, and rendered the 

 fish inconspicuous in the same way that 

 diiller colors are known to conceal spe- 

 cies found in less variegated environ- 

 ments, and for years this explanation 

 was widely accepted. It seems how- 

 ever that he exaggerated the color of the 

 reef background, which is as a whole of a 



1 Photographs by Mr. E. R. Sanborn of living fishes 

 at the New York Aquarium, and used in the Journal 

 through the courtesy of the New York Zoological 

 Society. , 



rather uniform gray or green tone with 

 only here and there bright areas. The 

 bold colors of certain stinging or dis- 

 tasteful insects are explained as a warn- 

 ing to possible enemies, which would be 

 expected more readily to learn to recog- 

 nize and avoid such species when boldly 

 colored. Professor Reighard of the 

 University of Michigan has done care- 

 ful experimental work on tropical fishes 

 to determine whether they might be 

 classed in the same category with 

 warningly colored insects, and has ob- 

 tained conclusive proof that their colors 

 are not of this character. Messrs. 

 Abbott H. and Gerald H. Thayer, in an 

 eloquent plea for the universality of 

 concealing coloration, follow Wallace in 

 the belief that the colors of reef fishes 

 actually do blend with their environ- 

 ment and render them inconspicuous, 

 although at first thought this does not 

 seem to be the case. The work of these 

 gentlemen has especial interest as it 

 approaches the problem with the pro- 

 fessional artist's knowledge of color 

 values. Dr. Charles H. Townsend of 

 the New York Aquarium has called 

 attention to the striking color changes 

 which certain species undergo. Such 

 changes often make for the concealment 

 of the fishes, but do not prove that the 

 bright colors when present have also a 

 concealing value. Often a single fish 

 has color patterns so different as to give 

 the impression of more than one distinct 

 species, but to anyone familiar with the 

 different fishes, the bright livery of each 

 is diagnostic. 



The center of abundance of aquatic 

 life is in the sea close to the shore. Here 

 exist many more varieties of fishes than 

 landward in restricted fresh waters, or 



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