whereas facultative cleaner fish rely on other food sources, such as demersal eggs or phytoplankton [1]. Where possible, both juveniles and adults of the same species that exhibited different body patterns and/or cleaning behavior were measured. We then compared the spectral reflectance of cleaner fish to 31 noncleaning species from the Labridae family whose colors have been measured previously [8] (Figure 1; Table S1). This family was chosen because it encompasses the majority of obligate cleaner fish, plus many facultative cleaners.