The pigment melanin contributes to the black edges (b) on the anal fin that are a sign of dominance, while pterins account for the red and yellow colors (a) on the anal fin, and signal health. Carotenoids on the caudal fin (c) indicate that the fish is eating well. Brighter, more-intense colors are associated with better mating success.

Photo by L. Brian Stauffer; graphic by Julie McMahon

Summary of the work

Built-in-billboards: Male bluefin killifish signal different things with different fins

Link to the PDF of the paper

The meaning of melanin, carotenoid, and pterin pigments in the bluefin killifish, Lucania goodei

Ashley M. Johnson Rebecca C. Fuller

Behavioral Ecology, Volume 26, Issue 1, 1 January 2015, Pages 158167