Life in the coral reef presents a great variety of adaptations in both form and behavior. Many of its inhabitants have exclusively adapted to the nocturnal life, where it seems easier to find food.
The squirrelfish has an intense red color and very large eyes relative to its body size, which gives it its name. These eyes are adapted for night vision. The inner part of the retina is lined with a tissue known as the “tapetum lucidum,” which has the property of amplifying existing light by a million times. This is why these nocturnal fish can roam the reef, searching for their favorite prey of invertebrates, illuminated only by the starlight.
This advantage in night vision becomes less valuable once the sun illuminates the reef. Additionally, due to its intense red color and relative slowness in swimming, it would become an easy target for faster predators. That’s why during the day, it usually hides in the crevices of rocks, small caves, or the cockpit of a submerged airplane, like the one in the photo. But once the sun sets, the reef will belong to them again, and countless squirrelfish will emerge from the depths of the coral, frantically traversing it with a hunting permit that expires at dawn.
“You cannot defend what you do not love, and you cannot love what you do not know.”