Black piranhas are small, generally about 20 cm long, but they have sharp triangular teeth in their mouths and hunt in groups. It is conceivable that this kind of fish is terrible.

The tank duckbill fish is related to catfish, but it has a sharp barbed tooth, with a body length of1.5-1.8 meters, and the largest can even reach about 2.5 meters, weighing more than 73 kilograms, and often appears in rivers between India and Nepal.

Crocodile finch eel, with a long barrel, a protruding snout, a short snout like a crocodile and two rows of teeth as sharp as daggers on its upper and lower jaws, and scales as hard as armor, can generally grow to 1.2- 1.8 meters, weigh 45-72 kilograms, and the longest can even grow to more than 3 meters.

Wolf fish, with wide jaws and two rows of sharp teeth, the largest eight incisors are half an inch long and generally about 1 meter long, which are 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 those of great white sharks. Its body is thick and fat (it is said that piranha is very delicious, with solid 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 meters 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 luminous antenna on its head and long sharp fangs in its big mouth. Although it is fierce, it is deep in the sea. ? ? ? In fact, it can only grow to about 12 cm and live in the deep sea about 900 meters away.

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 and almost touch their eyes. During the day, they stay at a depth of 5,000 feet (1524 meters), and at night, they come to less than 2,000 feet (609.6 meters) to prey. They are distributed in tropical to temperate waters all over the world.

The frilled shark, with a sharp tooth with 300 teeth and more than 25 rows, is about 1.5 meters long, and generally lives at the bottom of the sea 1500 meters, which is very rare.

Saw-bellied fat carp, with a human-like tooth, can grow up to 90 cm long and weigh more than 25 kg. It usually eats stone, fruit, small fish, aquatic vegetation and snails. Some rivers that mainly inhabit South America.

Goblin shark, which is pink but black in water, has a long fish kiss on its head to cover the sharp teeth under its nose. The long fish kiss has sensors and generally lives in the depth of 200 meters.