Serendip is an independent site partnering with faculty at multiple colleges and universities around the world. Happy exploring!

Flying Fish

Margaret Bohara's picture

How do flying fish fly?


What makes flying fish so special?


            As a kid, I was always enchanted by flying fish.  They seemed so wrong in the world – fish, that live and breathe and eat and breed in water, flying in the sky like birds.  For years, I didn’t think flying fish actually existed.  But I began to believe, little by little, and now have decided to base my final web paper on these magnificent creatures.  Where exactly do they live?  What exactly do they look like?  How exactly do they live?  Why exactly do they fly?

            There are two kinds of flying fish, Dactylopteri and Exocoetidae (1).  Dactylopteri are also called flying gurnards.  There are actually only three or four species found of the flying gurnards.  This type of flying fish can be distinguished from the Exocoetidae because it has a large, bony, spiky head, has large, hard scales, and has two dorsal fins.  On the other hand, there have been over fifty species of Exocoetidae discovered. Exocoetidae are also referred to as flying herrings because they are thought to resemble this non-flying fish.  Their one dorsal fin, their ventral fins placed backwards and below the middle of the body, and their small scales, also distinguish the Exocoetidae from the Dactylopteri.

            So what do these flying fish have in common (well, other than that they fly)?  Both the Dactyloperti and the Exocoetidae have huge pectoral fins.  These pectoral fins allow the flying fish to fly, or more literally, glide.  The flying fish’s pectoral fins can be compared to a bird’s wings.  Some four-finned fish also have giant pelvic fins that they can use to glide with.  The tails of flying fish are deeply lobed.  These fins help the flying fish push out of the water and into their glide.  The lower lobes of a flying fish’s tail also aid the flying fish with gliding (3).  The ventral fins of many Exocoetidae species are also very large, helping the fish to become airborne.

Diagram of the flying fish’s fins (3):

            Another physical difference between flying fish and non-flying fish, other than the size and shape of pectoral fins, is that flying fish have different-shaped eyes than most regular water bound fish.  You’ll find that most fish have curved corneas, helping them see better in the water.  But corneas of the flying fish are flattened so that they can also see when they fly (2).  Lastly, flying fish come in sizes ranging from four centimeters to forty-six centimeters.

            Flying fish live only in tropical and sub-tropical marine waters.  They live near the surface of the water and mostly eat plankton and small crustaceans (4), mainly feeding at night.  Flying fish lay eggs attached to long adhesive filaments that themselves attach to pieces of floating debris so that the eggs won’t sink into the water.  When the young fish hatches, it doesn’t look much like adult flying fish.  Young fish are usually different colors than adult fish, but they also have huge whiskers growing from their chins, sometimes even longer than the fish itself (3)!

            Predators of flying fish include sea lions and even dolphins.  Flying fish are also eaten by sea birds including frigate birds, boobies and noddies (5).  Competitors of the flying fish include tunas, snake mackerels, small deep-water fish, shrimp, and shifting layer fish (5).

            So why and how do flying fish fly?  Sorry to admit it, but flying fish don’t actually fly.  They glide.  You can usually find flying fish gliding in rough marine waters.  It’s believed that flying fish glide in order to escape predators.  Unless it’s a really clear day with still water, the predator will not be able to see the flying fish above the water because of refraction on the water’s surface (3). 

            In order leave the water, flying fish swim quickly upwards to the surface of the water and leap into the air.  Next, in order to glide, flying fish use their pectoral fins and the bottom larger half of their lobed tails as natural wings/gliders (3).  Unlike birds, though, flying fish do not flap their wings/fins.  This is why flying fish can’t fly, only glide.  By acting as a motor, the large bottom tail lobe helps the fish gain more height from the water and even helps the fish extend its airtime (3).  Flying fish can fly one meter above the water and their flights can last for 200 meters or more (2).

            But flying fish have to be careful!  Sometimes, if the wind is blowing too hard, the wind can pick up a flying fish and pull it sometimes even 20 feet above the water’s surface.  Sometimes the flying fish might even end-up falling onto a boat (1)!

            I’m not going to lie, I pretty much knew that flying fish didn’t really fly.  But I never knew how they glided, how they even left the water not to mention stay in the air.  And I always wanted to know why flying fish jumped and glided to begin with.  Most scientists believe that flying fish fly because they’re trying to escape predators.  But there are some who believe that the fish just want to fly.  And who can blame a fish for wanting to fly?