Indian legend says that Amazon puffer fish has a fantastic appearance.

Amazon puffer fish, also known as pink dolphin, is a freshwater mammal that lives in the Amazon River and the waterways of Bolivia and Peru. The pink dolphin is actually a puffer fish. They are smaller than other kinds of dolphins. These dolphins must live in warm shallow water, because their blubber is very low, and they can't stand the cold in deep water, so only warm water can keep them alive.

At present, Amazon puffer fish is the largest species found in puffer fish. The male is twice as big as the female, and the adult weight can reach more than 200 kilograms. At present, scientists have different views on whether Amazon puffer fish is actually one, two or three different species. Scientists have found that some Amazon dolphins can swim upside down, while others can't, so it is impossible to determine whether these lovely pink puffer fish are the same species.

Brazilian scientists published a study in a magazine, saying that the puffer fish in the Araguayan River is a unique species, namely the Araguayan puffer fish. The puffer fish living in Bolivia is another unique species. By 2022, IUCN only recognized three subspecies, namely Amazon puffer fish, Bolivian puffer fish and Orinoco river dolphin.

Pink puffer fish has a unique dolphin smile. They have round foreheads, slender mouths and conical teeth, which are used to catch small fish and other prey. The puffer fish's nose is very long, up to 0.5 meters, which is about four times that of dolphins. Amazonian dolphins have a two-cavity stomach, and they breathe by exhausting air through water jets.

These puffer fish are very flexible. They can make sharp turns in the water and like to swim backwards. Amazon puffer fish has no dorsal fin, but it has an evolutionary hump. This animal uses strong flippers and tails to cross rivers and areas rich in aquatic plants. Compared with marine dolphins, puffer fish swim very slowly. Their top speed is about 35 miles per hour. The reason is that their cervical vertebrae are not fused, but this gives the puffer fish more flexibility. The puffer fish can turn its head without moving its body.

It is worth mentioning that the brain of puffer fish is particularly large, and their IQ can be comparable to that of a 7-year-old human child. They often interact with humans. Pufferfish have unique ear adaptability, which can help them survive in underwater environment. Dolphins hear sounds from their throats instead of their ears, and puffer fish's ears are acoustically separated from their heads. The sinus bag separates the two body parts. This combination enables animals to enhance their directional hearing under water. Dolphins use high-frequency sounds to communicate, which enables them to produce sonar to locate. Sonar allows puffer fish to survive even if they are blind.

In addition, their eyes are on both sides of their heads. This means that their vision has two independent points, unlike humans. Researchers believe that puffer fish have poor eyesight, so many animals will die because of accidental contact with fishing nets. They are not aggressive to humans, so close to humans that many puffer fish have been killed by humans. At present, there are only 1500 Aragua puffer fish in the world.