Great Barracuda

Sphyraena barracuda can be found almost in all warm seas. It is also found in tropical areas of the Pacific as well as of the Atlantic Ocean. It prefers water temperature about 75 degrees of Fahrenheit but can be also found in colder waters. Its length usually does not exceed 2 metres and its weight is about 40 kg. Its agile silver coloured body has got 2 dorsal fins, large scales and large mouth with many exceptionally sharp teeth just suitable for biting. On its body there are several dark spots however there is no obvious difference between the male fish and the female one. The Great Barracuda is piscivorous, which means it eats other fish for instance: sardines, silversides, mullets, gobies, herrings but also small lizards and dolphins. Barracuda’s reproduction still remains unclear, but we know that the spawning takes place in spring. Its fertilized eggs are left with no care at all. It is a solitary fish and can be found in groups only when younger. The Barracuda might be a dangerous fish especially when provoked. Its sharp knife-like teeth have already caused a number of injuries to divers and swimmers. Barracuda’s meat can contain a poison so it is dangerous to eat it. It is also illegal to sell this fish. Nevertheless some people find its meat tasty. Credits go to: FISH

Mekong Giant Catfish

The world’s largest scaleless freshwater fish lives a tenuous existence in the murky brown waters of Southeast Asia’s Mekong River. Capable of reaching an almost mythical 10 feet (3 meters) in length and 650 pounds (295 kilograms), Mekong giant catfish live mainly in the lower half of the Mekong River system, in Cambodia, Laos, Thailand, and Vietnam. Once plentiful throughout the Mekong basin, population numbers have dropped by some 95 percent over the past century, and this critically endangered behemoth now teeters on the brink of extinction. Overfishing is the primary culprit in the giant catfish’s decline, but damming of Mekong tributaries, destruction of spawning and breeding grounds, and siltation have taken a huge toll. Some experts think there may only be a few hundred adults left. Mekong giant catfish have very low-set eyes and are silvery to dark gray on top and whitish to yellow on the bottom. They are toothless herbivores who live off the plants and algae in the river. Juveniles wear the characteristic catfish “whiskers,” called barbels, but these features shrink as they age. Highly migratory creatures, giant catfish require large stretches of river for their seasonal journeys and specific environmental conditions in their spawning and breeding areas. They are thought to rear primarily in Cambodia’s Tonle Sap lake and migrate hundreds of miles north to spawning grounds in Thailand. Dams and human encroachment, however, have severely disrupted their lifecycle. International efforts are under way to save the species. It is now illegal in Thailand, Laos, and Cambodia to harvest giant catfish. And recently in Thailand, a group of fishers pledged to stop catching giant catfish to honor the king’s 60th year on the throne. However, enforcement of fishing restrictions in many isolated villages along the Mekong is nearly impossible, and illicit and bycatch takings continue. Credits go to: National Geographic

The Beluga Whale

Belugas are also called white whales, and their unusual color makes them one of the most familiar and easily distinguishable of all the whales. Calves are born gray or even brown and only fade to white as they become sexually mature around five years of age. White whales are smallish, ranging from 13 to 20 feet (4 to 6.1 meters) in length. They have rounded foreheads and no dorsal fin. Belugas generally live together in small groups known as pods. They are social animals and very vocal communicators that employ a diversified language of clicks, whistles, and clangs. Belugas can also mimic a variety of other sounds. These whales are common in the Arctic Ocean's coastal waters, though they are found in subarctic waters as well. Arctic belugas migrate southward in large herds when the sea freezes over. Animals trapped by Arctic ice often die, and they are prey for polar bears, killer whales, and for Arctic people. They are hunted by indigenous people of the north, and by commercial fisheries that brought some populations, such as those in the Gulf of St. Lawrence, to near collapse. Beluga feed on fish, crustaceans, and worms. The whale is related to the tusked "unicorn" whale known as the narwhal. The beluga is not related to the sturgeon of the same name, which has been heavily fished for its famous caviar. Credits go to: National Geographic

Chinese Sturgeon

Chinese sturgeons are seasoned travelers, undertaking a round-trip journey of some 2,000 miles (3,500 kilometers) every year from the East China Sea to their spawning grounds in the Yangtze River. But in recent years this ancient cycle has been blocked by the Gezhouba Dam, built in the 1980s. Since that time subsequent dams have placed new, possibly insurmountable, hurdles in the sturgeons' upstream path and thrown the future of the species into serious doubt. Heavy shipping traffic, overfishing, and water pollution have also plagued Yangtze River waters and taken a heavy toll on these aquatic behemoths. Some scientists think fewer than a thousand individuals may remain. Chinese sturgeons can grow to enormous proportions, with large specimens topping 16 feet (5 meters) and 1,000 pounds (450 kilograms). These prehistoric-looking giants have a sharklike form, with large pectoral fins, a rounded snout, and rows of pronounced ridges running the length of their spine and flanks. Chinese officials have made efforts to safeguard the sturgeon, including curtailed fishing and the creation of a conservation area below the Gezhouba Dam to serve as an alternative spawning ground. They've also attempted to replenish the fish's dwindling numbers by breeding millions of fry in captivity and releasing them into their native rivers. So far such efforts have met with little success.Sturgeons may face long odds, but the fish has survival in its genes. Sturgeons have lived in the Yangtze for perhaps 140 million years, and this relic of the dinosaur era is sometimes dubbed a "living fossil." Some reports suggest the sturgeon may already be adapting to its changing environment. Studies suggest its diet is shifting from less abundant bottom dwellers, like clams, to more plentiful earthworms.
Credits go to: National Geographic

Sun Fish

As gigantic as the ocean sunfish can be, it still seems like only half a fish.
Sunfish, or mola, develop their truncated, bullet-like shape because the back fin which they are born with simply never grows. Instead, it folds into itself as the enormous creature matures, creating a rounded rudder called a clavus. Mola in Latin means "millstone" and describes the ocean sunfish’s somewhat circular shape. They are a silvery color and have a rough skin texture. The mola are the heaviest of all the bony fish, with large specimens reaching 14 feet (4.2 meters) vertically and 10 feet (3.1 meters) horizontally and weighing nearly 5,000 pounds (2,268 kilograms). Sharks and rays can be heavier, but they're cartilaginous fish. Mola are found in temperate and tropical oceans around the world. They are frequently seen basking in the sun near the surface and are often mistaken for sharks when their huge dorsal fins emerge above the water. Their teeth are fused into a beak-like structure, and they are unable to fully close their relatively small mouths. Ocean sunfish can become so infested with skin parasites, they will often invite small fish or even birds to feast on the pesky critters. They will even breach the surface up to 10 feet (3 meters) in the air and land with a splash in an attempt to shake the parasites. They are clumsy swimmers, waggling their large dorsal and anal fins to move and steering with their clavus. Their food of choice is jellyfish, though they will eat small fish and huge amounts of zooplankton and algae as well. They are harmless to people, but can be very curious and will often approach divers. Their population is considered stable, though they frequently get snagged in drift gill nets and can suffocate on sea trash, like plastic bags, which resemble jellyfish.
Credits go to: National Geographic

Queen Angelfish

Queen angelfish get their royal title from the speckled, blue-ringed black spot on their heads that resembles a crown. Decked out with electric blue bodies, blazing yellow tails, and light purple and orange highlights, Queen angels are among the most strikingly colorful of all reef fishes. Their adornments seem shockingly conspicuous, but they blend well when hiding amid the exotic reef colors. They are shy fish, found either alone or often in pairs in the warm waters of the Caribbean and western Atlantic. Fairly large for reef-dwellers, they can grow up to 18 inches (45 centimeters) in length. They have rounded heads and small beak-like mouths, and, like other angelfish, their long upper and lower fins stream dramatically behind them. Their diet consists almost entirely of sponges and algae, but they will also nibble on sea fans, soft corals, and even jellyfish. Queen angels are close relatives of the equally striking blue angelfish. In fact, these two species are known to mate, forming natural hybrids, a very rare occurrence among angelfish.
They are widely harvested for the aquarium trade, but are common throughout their range and have no special protections or status. Credits go to: National Geographic

Parrot Fish

It's hard to decide which of the colorful parrot fish's many unique characteristics is most remarkable. There’s its diet, which consists primarily of algae extracted from chunks of coral ripped from a reef. The coral is pulverized with grinding teeth in the fishes’ throats in order to get to the algae-filled polyps inside. Much of the sand in the parrot fish's range is actually the ground-up, undigested coral they excrete. There's its gender, which they can change repeatedly throughout their lives, and their coloration and patterns, which are a classification nightmare, varying greatly, even among the males, females, and juveniles of the same species.
Finally, there are the pajamas. Every night, certain species of parrot fish envelope themselves in a transparent cocoon made of mucous secreted from an organ on their head. Scientists think the cocoon masks their scent, making them harder for nocturnal predators, like moray eels, to find. Close relatives of the wrasse, parrot fish are abundant in and around the tropical reefs of all the world’s oceans. There are about 80 identified species, ranging in size from less than 1 to 4 feet (30 to 120 centimeters) in length. Their meat is rarely consumed in the United States, but is a delicacy in many other parts of the world. In Polynesia, it is served raw and was once considered "royal food," only eaten by the king.
Credits go to: National Geographic