Natural History

Masters of Disguise

These fish have perfected the game of aquatic hide-and-go-seek.

Story By Suzanne Gerber ~ Photos By Barbara Shively

We get the English word camouflage from the  French camoufler (to disguise), which likely derived from camouflet, meaning “a puff of smoke” or “smoke blown in someone’s face as a practical joke.” But to fish, who exist in an eat-or-be-eaten world, survival is no joke. Humans have a veritable arsenal of self-protective means, but marine animals rely on just a few: the strike-first (or better) philosophy, the swim-faster approach, or the old hide-out-in-plain-sight routine. Some fish, of course, change color in the course of their mating rituals, but that’s a subject for another time. Here we’ll take a look at four absolute masters of disguise: the scorpionfish, the peacock flounder, the southern stingray, and the flying gurnard, who over the millennia have evolved and perfected their game of aquatic hide-and-go-seek.

Now you see me . . .

There are a few primary types of underwater camouflage: deploying what’s known as cryptic camouflage, a creature blends in with his environment or disguises himself as something uninteresting-or, better yet, something dangerous. This can be a permanent affectation (like a stonefish or scorpionfish) or temporary (a trumpetfish that can change from bright blue to yellow to olive before your very eyes). Some peripatetic organisms actually change their colors or patterns continuously as they move across different colored backgrounds. Now there’s a sight to behold!

Often a critter will imitate the movement of something else in nature (grass blowing, something leafy fluttering in the water column); this, not surprisingly, is called mimicry.  And finally, using simple protective camo, certain fish will attract or attach foreign materials to their body to hide beneath.

The science behind camouflage is complex enough to earn serious students degrees in the subject, but to simplify things, we can attribute disguise-behavior to either the employment of pigment cells, called chromatophores, which the animal can control through his nerves or hormones (as in octopi and many color-changing fish), or to a change in diet (like the nudibranch). Fish have the ability to concentrate their chromatophores into the center of each cell, giving them a lighter appearance, or they can expand the pigmentation over a larger area and make the color all the more intense. There have even been reports from snorkelers and divers that certain species of fish have gotten close enough and stuck around long enough to alter their camouflage to match the human’s swimsuit!

Depending on whether they’re active in the daytime or at night, different species will utilize different types of color camo. At night when they’re resting, diurnal fish often effect what’s called disruptive coloration-blotchy patterns like bold stripes that alter their silhouette and make them hard to distinguish from the background. Nocturnal (and some deepwater) fish are red, because underwater, everything loses its color in accordance with the ROY G. BIV spectrum, and red is the first color we lose. Instead, it looks merely dark, and those fish become nearly invisible at depth or in the dark. This is why if you ever cut yourself underwater, it seems to bleed black or blue. You haven’t turned into a blueblood, it’s just the underwater law of nature, and fish are the true juris doctors.

scorpian3verticalScorpionfish

The Caribbean scorpionfish is related to the Pacific stonefish, and both are extraordinary creatures. Some snorkelers and divers consider this the ugliest fish in the world (certainly the poutiest), while others regard it as one of the most glorious sights in the ocean. This lumpen creature just sits around rocks on coral reefs, hiding out rather conspicuously (once you learn to recognize him) and waits for his next meal to swim by unawares. He’s got the distinction of being the fastest shot underwater, able to grab and swallow prey in .015 seconds! This innocuous-looking fish is also poisonous (particularly cousin Stoney), with his 13 needle-like (but deceptively powerful) spines that shoot out venom if pressed. The poison is painful, capable of numbing the body instantly and induing heart failure.

New divers are always impressed by divemasters who seem to have personally placed down and positioned scorpionfish, so uncanny is their ability to pick them out of the matching environment. But with practice, you, too, can spot your own scorpion. Last February, my dive buddy John was very proud of himself for finding three in a row on a single dive, each one larger and harder to detect than the last!

flounder2Peacock flounder

This sand-sweeping, lightly spotted cutie changes its color and pattern to blend in perfectly with the ocean floor. Their rolling eyes stick up on little stumps above the dorsal side of their body to give them a better view of the environment. Each eye moves independently-so he can look in two directions at once.  But it also makes him vulnerable: if the eye gets covered by sand and the flounder can’t assess his surroundings, his camo won’t work.

You may not realize this, but when it’s born, a flounder actually has one eye on each side of its face and swims upright, like other fish. But as he matures, one eye migrates until the two are close together on the same side of the head. Because his mouth doesn’t move, he develops a lopsided face-all the funnier-looking because of his sideways swimming. Barbara and I love to “hunt” for them in the sand. Sometimes, when we’re been in just the right place at the right time, we’ve seen half a dozen on a single dive.

Flying gurnards

These well-camouflaged creatures live on shallow sandy bottoms, sometimes alone, often in pairs and occasionally-as Barbara, her husband Dick and I discovered a few years ago on a muck dive in Grand Turk-in groups of three, four and even five! We had the thrill of our diving careers when on that single dive (OK, it was 100 minutes long), we counted 15 gurnards!

Although slow-moving, gurnards can turn rather feisty when excited (around divers, say, or when feeding or mating). This is when you want to see them. Their plain, lizard-like bodies are transformed Cinderella-like, and when they fan their pectoral fins (which you would swear are wings), they’re as glorious as any land peacock. And while they can move swiftly, they don’t technically fly. We humans love the show, but believe it or not, potential predators are usually scared off. Mission accomplished!

stingray2-6-10Southern stingrays

These exotic, outer-spacey creatures are characterized by their large, flat, diamond-shaped disks and lack of distinct head. And what could be a better disguise for a creature that spends half his life burrowed in the sand than a dark upper body and white belly? To divers and predators, often the only peekaboo is the pair of eyes poking out of the sand. It’s a thrill (and occasionally gives a start) to be finning along and suddenly realize those “stones” you’re passing over in the sand are actually the eyes of a buried six-foot-long stingray!

They are truly remarkable animals: because of those top-mounted eyes, they depend on electro-receptors and keen senses (smell and touch) to locate food. A preferred method is to uncover buried prey, like crabs, shrimp, clams and worms, by forcing jet streams of water through their mouths or flopping their fins over the sand.

When they shuffle in the sand it’s a heart-pounding site-as is watching them lift off and glide through the water, gently flapping their “wings” like an extraterrestrial. By the way, the stingrays we find in the Caribbean are benign and not the same species that stung and tragically killed Steve Irwin.

New York-based Suzanne Gerber writes about scuba, travel and health for a variety of publications. Book your next dive trip by contacting Suzanne at suzanne@worldofdiving.com.

Avid underwater photographer Barbara Shively discovered Grand Turk diving in 1997 and has returned every year. It is her passion to share the coral reefs’ beauty through her photographs, many of which can be viewed and purchased at http://shivelygallery.com/. A variety of her prints are on sale at Art Provo, located in The Regent Village, Providenciales.



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