Black piranhas are small, generally about 20 cm long, but they have sharp triangular teeth in their mouths and hunt in groups. You can imagine how terrible this fish is.

The tank duckbill fish is related to catfish, but it has sharp barbed teeth, with a body length of 1.5- 1.8 meters, and the largest can even reach about 2.5 meters, weighing more than 73 kilograms. It often appears in rivers between India and Nepal.

Crocodile eel has a long cylindrical body, a prominent nose and mouth, a short nose and mouth like a crocodile, and sharp teeth with two rows of daggers on the upper jaw. Its scales are as hard as real nails, and can generally grow to 1.2- 1.8m, weighing 45-72kg, and the longest can even grow to more than 3m. "As long as it is a creature in the water, it is almost universal.

Wolf fish, with a wide jaw and two rows of sharp teeth, the largest eight front teeth are half an inch long, generally about 1 meter long, widely distributed in the Pacific Ocean and the East Atlantic Ocean, inland coastal areas and fresh water areas.

African piranha, also known as giant piranha, has 32 teeth, which are similar in size to great white sharks. Its body is thick and fat (piranha is said to be delicious, with strong meat and low fat content). Because it is good at jumping out of the water, it is still the favorite species of anglers, which can generally grow to about 70 cm, but some giant piranhas can reach 1.8 m in length and weigh more than 57 kg. Living in some rivers in Congo

Deep sea? ? ? ? This kind of deep-sea fish looks strange. Its round body looks like a basketball. It has a glowing antenna on its head and long, sharp fangs in its big mouth. Although fierce, the sea is deep. ? ? ? In fact, it can only grow to about 12 cm and live in the deep sea of about 900 meters.

The viper is slender and flat on its side, generally less than 35 cm in length. They have big mouths and long fangs, and their lower teeth bend backwards, almost touching their eyes. During the day, they stay at a depth of 5000 feet (1.524 meters), and at night, they come to less than 2000 feet (609.6 meters) to hunt. They are distributed in tropical to temperate waters all over the world.

Wrinkled shark, with sharp teeth, has 300 teeth, more than 25 rows, about 1.5 meters long, and lives on the seabed of about 1.500 meters, which is very rare.

Saw-bellied fat carp, with human-like teeth, can grow to 90 cm long and weigh more than 25 kg. It usually eats stones, fruits, small fish, aquatic plants and snails. Some rivers mainly distributed in South America.

Leprechaun shark, pink but black in water, has a long fish kiss on its head to cover its fangs under its nose. Long-nosed fish have sensors and generally live at a depth of 200 meters.