The Colour Vision of Fish

At one time during the past few months the writer's attention was called to the following statement made in January I926 by an eminent surgeon: "In fishes a falci-ft \form ligament is attached to the back of the lens and to the back of the eye for N /fX,E1 focusing. They have no color vision. This fact will be disputed by those who sell q .; ~~~artificial flies at high prices.""5 A subse-"~ Xe\X Xt quent investigation of the reference23 which had been used as the authority for that statement led to a study of the literature concerning the colour vision of fish. The available evidence upon this subject may be arbitrarily divided, for the purpose of discussion, into three classes: the empirical, including the opinions of our more leisurely ancestors; that derived by observation of, or experiment upon, the adaptability of fish to their environment, and their colour changes under various circumstances; and the experimental evidence obtained by the employment of such psychological concepts as association , memory and choice. It is the sole purpose of this paper to present some of the more significant, amusing, or informative phases of this subject in the form of a review of the literature. From the earliest times the habits of fish have interested man. The Romans, as early as the first century, often had living fish brought to the banquet table and then had them immersed in warm water that the ladies might enjoy the beautiful changes in colours which they showed while dying! 17 But however much their habits were studied, their senses seem to have been rarely discussed. Even in 1774 the learned Oliver Goldsmith7 can only assure us that, "See-ing seems to be the sense fishes are possessed of in the greatest degree ." Neither he nor Gilbert White30, who studied fish attentively , make a specific mention of their colour vision.