Investigating the behavioral significance of color pattern in a cichlid fish: firemouths Thorichthys meeki respond differently to color-manipulated video and dummy conspecifics

Red coloration is a conspicuous feature of many visual signals and can function to attract or deter its viewers. Among fishes, red is associated with specialized nuptial, territorial and aposematic (warning) displays. Both sexes of the firemouth cichlid fish Thorichthys meeki develop red ventral coloration at sexual maturity, along with temporally variable black (melanic) elements. Isolated adult firemouth cichlids sequentially presented paired dummy and paired video conspecifics, both with and without red ventral coloration. Subjects interacted more with red-containing stimuli, but with a significant interaction: dummy presentations revealed a strong, positive red bias that video presentations did not. In addition, the melanic color pattern displayed by subjects at the initiation of each trial had a significant effect on subject responsiveness. These results reveal the potential for between-subject differences and experimental design parameters to interact critically in the study of animal color patterns.