Photograph by Paul Nicklen
The striped surgeonfish is an attractive Indo-Pacific reef fish that’s best handled with care because its caudal spine is venomous. Scientists believe that the world’s seas hold some 1,200 different venomous fish species and estimate that they injure about 50,000 people per year. But fish venoms can also bring great benefit—they are useful in the development of new drugs.
Photography by Valeria Paoletti, My Shot
Barracudas are long, lean hunting machines. Their sleek bodies enable them to dart through the water at speeds of up to 25 miles an hour (40 kilometers an hour) in pursuit of fish to shred and devour with their razor-sharp teeth. The barracuda is highly evolved to be a master predator in its environment—the fish has been honing its skills for some 50 million years.
Yellow Sea Anemone
Photograph by Jeffrey de Guzman, My Shot
The sea anemone may look like the beautiful flower for which it’s named, but fish that swim too close may regret it. The anemone, which is related to corals and jellyfish, uses venom-laden tentacles to stab passing victims with a paralyzing neurotoxin—rendering them helpless and fit to be eaten.
Photograph by Heather Perry
A moray eel eyes a colorful fish in the waters off Kona, Hawaii. If the eel decides to pounce the fish may soon be snared by not one but two sets of toothy jaws. The second set, found in the eel’s throat, surges forward to grab prey and help draw it to its doom. This unusual ability allows the eels to gulp large animals without having to open wide in the tightly confined spaces of the reef holes in which they live.
Great White Shark
Photograph by Raul Touzon
There is no doubt that the great white shark sits atop the ocean food chain. The world’s largest predatory fish can weigh in at over 5,000 pounds (2,270 kilograms) and reach lengths of more than 20 feet (6 meters). Great whites boast some 300 teeth, which they typically sink into sea lions, seals, small toothed whales, sea turtles, and carrion. These sharks are responsible for a third to a half of the 100-odd shark attacks on humans every year, but the strikes are usually unintentional and rarely prove fatal.
Photograph by Paul Nicklen
School is in session for a group of whitespotted surgeonfish on a Kiribati, Micronesia, coral reef. The world’s 75-odd species of surgeonfish have scalpel-like, movable spines on each side of their tail bases, which can deliver a painful slash to another fish or a curious human hand. Despite this weapon, surgeonfish aren’t particularly violent. Most are grazers that feed on ocean algae.
Photograph by Marilyn & Maris Kazmers/Seapics.com
An oversized head and a large, frowning mouth give the oyster toadfish the look of a tough customer—and in this case appearances are not deceiving. This bottom-dwelling camouflage artist can crush mollusk shells with its jaws and strong teeth, and devour oysters, crabs, shrimp, squid, fish, and a host of other marine creatures. But oyster toadfish males have a soft side. They guard the nest and even keep watch over young hatchlings during their first few weeks of life.
Photograph by David Doubilet
Needlefish are commonly seen schooling near the surface of tropical and subtropical waters. But they can also hurl themselves out of the water, and once airborne they can become dangerous flying daggers. Though it is rare, people have been seriously hurt and even killed when stabbed by the fish’s sharp, elongated jaws. Night fishermen in small boats are at particular risk because their lights may attract the fish.
Textile Cone Snail
Photograph by De Agostini/Getty Images
This innocuous-looking snail is actually one of the planet’s most toxic creatures. Textile cone snails “harpoon” their prey with hollow teeth, through which they inject a lethal venom. Their most common victims are mollusks, though the snails have been known to eat their own kind when meals are scarce.
Photograph by James Walters, My Shot
Saltwater crocodiles, or “salties,” are the world’s largest crocodilians, sometimes stretching 23 feet (7 meters) in length and topping 2,200 pounds (1,000) kilograms. Yet these crocs hunt by stealth, lying in wait below shoreline waters to snatch crabs and turtles or spring upon thirsty animals that have come to drink. Saltwater crocs kill a number of people each year, but suffer far more at human hands than vice versa.
Photograph by Joe Platko, My Shot
A small crab hovers unharmed among the venomous tentacles of a colorful sea anemone. Though anemones are toxic, they are known to enjoy several symbiotic relationships. Some species provide safe pasture for green algae to grow and in turn receive oxygen and sugar from photosynthesis. Clownfish also dwell among the tentacles, where those messy eaters provide their anemone hosts with plentiful table scraps.
We are committed to protecting the last wild places in the ocean.
From the Channel
Support the Ocean
Help protect the last healthy, undisturbed places in the ocean so we can learn how to help healthy reefs thrive, help unhealthy reefs recover, and better preserve the ocean.
Explore the Ocean
Order ocean books, DVDs, maps, and more from the National Geographic online store.
Explore the world's oceans, from their prehistoric beginnings to modern-day efforts to preserve their natural wonder.
Immerse yourself in the wonders of the deep through colorful maps, photos, and satellite images.
Engage, Conserve, Restore
The National Geographic Society’s freshwater initiative is a multi-year global effort to inspire and empower individuals and communities to conserve freshwater and preserve the extraordinary diversity of life that rivers, lakes, and wetlands sustain.