The Stonefish - Synanceia is fish from Synanceiidae family, also known as the Stonefish. It is one of the most poisonous fish on earth. The Stonefish is found in the coastal regions of the Indo-Pacific oceans. They are mostly found in sea or oceans, at times can also be found in rivers. The deadly neurotoxin in their glands is injected in the enemy through the needle like dorsal fin spines which erect when threatened or suspect danger. Their camouflage is very effective. At times divers have stepped on them thinking they are stones. The Toxin from this fish can cause temporary paralysis and death if left untreated.
Barracudas - 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.
Catfish - They may look innocent and peaceful with their cute little whiskers, but Catfish are dangerous creatures if provoked. When it feels threatened, the Catfish pulls out three barbed spines from its back and side fins. They are venomous and cause severe pain. Although rare, throughout the years there have been cases when catfish attacks proved deadly. Catfish venom remains active for several days after the fish dies so even refrigerated ones must be handled with care.
Striped Surgeonfish - 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.
Tiger Shark - The Tiger Shark or Galeocerdo Cuvier is one of the species of Shark. These sharks can grow up to 5 meters in length. They are usually found in tropical or temperate oceans. These deadly Tiger Sharks are found near central Pacific islands and are mostly night time hunters. These savage predators can eat anything from fish, seal, small sharks and even birds flying above the water. The Tiger Sharks have powerful jaws which they can easily crush a sea turtle or any other marine mammal. They have excellent vision and sense of smell which allows them to find a drop of blood in the football ground.
Great White Shark - 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.
Yellow Sea Anemone - 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.
Stingrays - Not many people really knew how dangerous stingrays really were until the terrible accident in which Steve Irwin lost his life. The truth is stingrays kill a lot more people than sharks for example. They are not aggressive creatures and when attacked, most of the time they just flee, but when stepped on, stingrays whip their tail stinger.
Puffer Fish - These funny looking Puffer fish are the second most poisonous vertebrates on earth after the Golden Poisonous frog. The puffer's skin and certain internal organs are highly toxic to humans. Deadly poison called Tetrodotoxin (TTX) is contained Puffer fish. Toxins are more powerful than cyanide resulted in difficulty in breathing on a person before leading to death. Still in some parts of Japan and Korea chef's remove the poisonous part and meat allowing it to be served as meal.
Moray Eel - 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.