Bioluminescence is the capability of animals, fungi or bacteria to produce light. Bioluminescence is one of the most fascinating phenomena in animal kingdom and has been independently developed during evolution many times. Surprisingly, very little information is available about the function and importance of bioluminescence for animal behavior. One of our main goals is therefore to understand the role of the bioluminescent signal from flash light fish for the behavior in its native environment and in the lab, and how the signal is processed in the fish brain. Flash light fish live close to the surface from coral reefs in for example Egypt and Indonesia.