These bottom dwellers do not respond to color differences when tested in shallow waters. Perhaps that's the color they prefer. If so, they have for a long time. Seeing in color has helped animals survive through the ages. Fish may choose red, through an evolutionary process, to elude predators.
Red fish live in dark waters.
Thus red is good camouflage. In deep water or at night, red appears gray. It spends daylight hours in caves and emerges at night to forage among coral reefs for prey.