Goldfish in the Study of Color Vision and Perception of Color in Nature

Date of Award


Document Type

Restricted (Opt-Out)

Degree Name

Bachelor of Science



First Advisor

Leo Fleishman




goldfish, vision, tetrachromat, visual system, lower vertebrates


Many animals, including humans, have evolved the use of color vision. It cannot be assumed, however, that animals perceive or detect color in the same way that humans do. This study aimed to both test the feasibility of goldfish as a viable model for studying animal color vision, and to address questions about perception of color in nature by animals. We were particularly interested in assessing the role that color contrast – the difference between the color of an object and its background – plays in making objects more or less visible. We were interested in determining whether goldfish exhibit color categorization: the tendency to perceive certain different colors as fundamentally similar, and if it is similar to the same process in humans. We trained goldfish to feed from a plastic holder that contains a brightly colored mark near the food release point. Our goldfish rapidly learned to identify the color orange with a food reward.

We then used this basic response to test how different stimulus/background color combinations alter response probability. We also tested categorization by measuring the tendency to approach novel colors that differ from the training color in various ways. It was found that orange was more visible to the goldfish against a green background than an orange one. Furthermore, clear evidence was found supporting color categorization in a way that is similar to humans; the goldfish tended to associate both red and yellow with orange.

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