Underwater's Masters of Disguise

Coleman shrimp

Photograph by Tim Laman

The vivid Coleman shrimp has developed the perfect camouflage for its perch amid the venomous spines of a fire urchin in Komodo National Park, Indonesia. The blue tips of the urchin’s spines are filled with toxic venom, but the shrimp is able to live comfortably among them without injury.

Reef stone fish

Photograph by Jeff Rotman/Getty Images

The reef stonefish haunts coral reefs across the Indo-Pacific. It’s not always easy to spot, because it blends so well with its rock and coral surroundings, but divers are best to be on the lookout for the colorful fish. The stonefish’s 13 dorsal fin spines can prove most unlucky for anyone pricked by them—they carry one of the most toxic fish venoms in the world.

Toadfish

Photograph by Kristian Taylor, My Shot

The toadfish croaks like its amphibian namesake but typically looks more like the seafloor surroundings where it lies in wait for prey. The fish also has a remarkable tolerance for ammonia, 10 to 20 times greater than that of a human. Scientists studying how the toadfish survives such toxins say the humble animal could someday help produce medical treatments for human ailments including liver disease, stroke, heart attack, and brain injury.

Leafy Sea Dragon

Photograph by Armand Poblete, My Shot

The leafy sea dragon has evolved an uncanny resemblance to the seaweed and kelp found in Australian coastal waters. The animals also mimic leafy weeds by drifting along with ocean currents, snacking on sea lice or tiny crustaceans. Male sea dragons bear young, like their relatives the sea horses, carrying eggs underneath their tails for four to six weeks.

Leaf Scorpion fish

Photograph by Tim Laman

The leaf scorpionfish doesn't just look like a leaf—it sometimes acts like one, swaying from side to side in the currents like a dead leaf tumbling among grasses or algae. Woe to the small crustacean or fish who is fooled—the scorpionfish's strike is that of a formidable predator.

Cuttlefish

Photograph by Wolcott Henry

The cuttlefish, actually a cephalopod relative of octopuses and squid, can shift shape and change its skin color to hide from danger by impersonating its surroundings—like a chunk of a coral, a clump of algae, or simply a patch of sand. The animal’s skin holds some ten million color cells and functions like a high-definition TV that fine-tunes color change so effectively the U.S. military has studied the animal in hopes of improving its own camouflage techniques.

Crocodile fish

Photograph by Darlyne A. Murawski

The eyes of the crocodile fish reveal how remarkably well the ambush hunter has evolved to the seafloors and reefs where it typically lies in wait. Frilly iris lappets, which look like seafloor sand, break up the eye’s black pupil to conceal this master of camouflage even more.

Mimic octopus

Photograph by David Doubilet

The mimic octopus is an intelligent shape changer that can impersonate a host of other animals to dodge hungry predators.

The cephalopod can alter its appearance by, among other ruses, flattening out to appear as a poisonous sole, swimming surrounded by its floating arms to impersonate the lionfish and its venomous fins, and changing the colors on its arms to make them look like poisonous sea snakes.

Source: ocean.nationalgeographic.com