Certain fish species launch themselves from the water and glide through the air. These fish are not truly flying in the same way birds do, but rather performing impressive glides. This ability showcases remarkable adaptations and a unique evolutionary path in the marine environment.
How Fish Propel Themselves Through Air
The ability of these fish to exit the water and glide involves speed, specialized anatomy, and precise body control. To initiate an aerial excursion, a fish generates significant speed underwater, reaching velocities of up to 35 miles per hour (56 kilometers per hour) just before breaking the surface. This rapid acceleration is achieved through powerful, rapid side-to-side movements of their deeply forked tails. As the fish approaches the surface, it angles its body upwards, using the momentum to emerge from the water.
Once airborne, the fish spreads its enlarged pectoral fins, which can span up to two-thirds of its total body length, acting like fixed wings. These fins are not flapped like a bird’s wings but are held rigid to generate aerodynamic lift. Some species also possess enlarged pelvic fins that provide additional lift, functioning as a second set of wings. The lower lobe of their caudal fin, or tail, often remains in the water briefly after the body lifts off, allowing the fish to continue sculling rapidly for additional thrust and stability as it transitions into the air.
The fish can adjust the angle of its pectoral fins to control its trajectory and maintain stability during the glide. Glides can cover distances of up to 650 feet (200 meters) and last for several seconds, sometimes even longer with favorable wind conditions. While in the air, their streamlined bodies minimize drag, allowing for efficient movement. This entire process is a controlled maneuver, not a random leap.
Reasons for Aerial Excursions
The primary motivation for these fish to launch themselves into the air is predator evasion. Many fast-swimming marine predators actively hunt these fish just below the ocean’s surface, including tuna, dolphins, marlin, and swordfish. By breaching the water, the fish can momentarily escape these aquatic hunters.
This aerial escape serves as a short-term defense mechanism rather than a method of long-distance travel. The brief time spent airborne allows the fish to gain distance from its pursuer before re-entering the water, often in a different direction. While predator escape is the dominant reason, some researchers suggest that strong winds might occasionally assist in longer glides, potentially aiding in energy conservation or helping them cover small distances to new feeding areas.
Common “Flying” Fish Examples
The most well-known “flying” fish belong to the family Exocoetidae, which encompasses over 40 species distributed across tropical and subtropical oceans worldwide. These species are characterized by their large, wing-like pectoral fins. Two-wing species, like those in the genus Exocoetus, primarily rely on their large pectoral fins for lift. They often have a more streamlined body shape optimized for speed.
Other species, such as those in the genus Cypselurus, are known as four-wing flying fish because they also possess enlarged pelvic fins that contribute to lift. These four-winged varieties generally achieve longer glides due to the increased surface area for lift. Their bodies are typically silvery, helping them blend with the ocean surface from above and the sky from below, providing camouflage during their aerial escapes. These fish are commonly found in the open ocean, far from coastal waters, where their unique escape strategy is most effective against pelagic predators.