Fig. (1) Images show two specimens of the blue-colored phenotype of rainbow trout, sorted in contrasting color categories based on Blue Color Intensity on the back (BCI). a) Specimen of Low-BCI category (BCI < 50%) and b) individual of High-BCI category (BCI ≥ 50%). The BCI was defined as the percentage of skin area covered by blue/sky-blue hues [(number of matching pixels of blue/sky-blue hues/total number of pixels) x 100] registered within the 3 x 3 cm area of the back skin located in front of the dorsal fin. The region of interest is represented by an expanded rectangle.