Does soil color affect fish evolution? Differences in color change rate between lineages of the sailfin tetra

Several organisms match their skin color to the prevalent background color, avoiding potential predators. In this paper, we investigated differences in the rates of color change among populations of the Amazon fish sailfin tetra (Crenuchus spilurus) that represent lineages that live in regions of different soil types. Populations inserted into blackwaters (sandy soil) showed higher rates of color darkening in response to exposure to a dark environment composed by dead leaves than the population inserted into clearwater (clayed soil). Here we showed that coloration of the soil type can affect the rate of the body color change in Amazon fishes.