9 Monsters of the River of the World

1. African Lungfish

Lungfish (also known as salamanderfish) are freshwater fish belonging to the subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton.

2. Goliath Tigerfish

A recent, unprecedented river run on the Congo yielded a raft of new discoveries, including different species--some potentially new--in nearly every nook and cranny, scientists announced this week.
The river was also found to be possibly the world's deepest, and its extraordinary changes in depths and currents help explain why it's such a hotbed of fish diversity.

3. Vampire Piranha

Vampire Piranha is kind of the famous piranha fish of the Amazon river. The fish is called piranha because vampire it fangs that can reach 6 inches. This little-known piranha fish live in the river Orinoco, Venezuela.

4. Mekong Giant Catfish

The Mekong giant catfish is perhaps the most interesting and most threatened species in the Mekong river. For this reason conservationists have chosen it as a sort of “flagship” species to promote conservation on the Mekong. With recorded sizes of up to 10.5ft (3.2m) and 660lb (300kg), the Mekong’s giant catfish currently holds the Guinness Book of World Records' position for the world’s largest freshwater fish.

5. Bagarius yarrelli

Bagarius yarrelli, known as the Giant Devil Catfish or Goonch is a very large species of catfish in genus Bagarius found in rivers in South Asia.It is possibly also found in Southeast Asia, but this may involve a separate species.

It is found in large rivers, including rivers with fast current, but never in small streams. It is found in South Asia. There are also populations in Southeast Asia (as far south as Sumatra and Borneo), but this may involve a separate species.

This fish reaches up to 2 m (6.6 ft) in length. It may be largest species in the genus. The related B. bagarius, another species where there is considerable taxonomic confusion, has–perhaps in error–been reported as reaching the same size as B. yarrelli, while others considers B. bagarius to be a dwarf species that only reaches about 20 cm (7.9 in).

6. Alligator Gar

The Alligator Gar ("Gator Gar"), Atractosteus spatula, is a primitive ray-finned fish. Unlike other Gars, the mature Alligator Gar possesses a dual row of large teeth in the upper jaw. Its name derives from the alligator-like appearance of these teeth along with the fish's elongated snout. The dorsal surface of the Alligator Gar is a brown or olive-color, while the ventral surface tends to be lighter. Their scales are diamond-shaped and interlocking (ganoid) and are sometimes used by Native Americans for jewelry and arrow heads.

7. Pirarucu

Pirarucu (Arapaima gigas), also called arapaima or paiche , pirarucu [Credit: Hans Reinhard/Bruce Coleman Ltd.]ancient, air-breathing, giant fish of Amazonian rivers and lakes. One of the largest freshwater fishes in the world, the pirarucu attains a length of nearly 3 metres (10 feet) and a weight of 220 kg (485 pounds). The fish has a peculiar profile in that the front of the body is long and narrow, whereas the rear is flat and possesses only a rudimentary, rounded tail.

The pirarucu is a fish belonging to a primitive group of carnivorous bony-tongued fishes, the Osteoglossidae, that crush their prey with a large tongue studded with teeth. Amazonian people, in fact, use dried pirarucu tongues as seed-graters. This fish is also an important protein source in the diet of people living along the river, but large pirarucu have become less common in some areas, owing to overfishing.

8. Chinese Paddle Fish

Chinese Paddlefish, Psephurus gladius (simplified Chinese: 白鲟; traditional Chinese: 白鱘; pinyin: báixún), also known as Chinese Swordfish, are among the largest freshwater fish. It is one of two extant paddlefish species, the other being the American Paddlefish (Polyodon spathula). It is also called "elephant fish" (象魚; xiàngyú) because its snout resembles an elephant trunk. It is recorded sometimes in Classical Chinese as wěi-fish (鮪). More poetically, it is sometimes referred to as the "Giant Panda of the Rivers", not because of any physical resemblance to a panda, but because of its rarity and protected status.

The Chinese Paddlefish is the People's Republic of China's first-level protected animal. Its belly is white and back and head grey. They live mostly in the middle or lower part of the Yangtze (Chang Jiang), occasionally in large lakes. They feed on other fish, as well as small amounts of crabs and crayfish. Paddlefish are sexually mature at age seven or eight, with a typical body length of 2 metres and a weight of 25 kilograms.

9. Piraiba Catfish

This fish can reach 3 feet in length and its weight is 272 kg.  This size scaring most anglers. This Fish is known for its strength, this fish is said to be able to even make a man drowning because of its strength.
Many rumors spread the cause of missing anglers that fishing in the river is being dragged by this fish into the river until they are drowning.

Apparently the river is not lost to the sea, many unique creatures living in the river. They are physically unique and weird, indeed. It is undeniable that  the earth still has more unique creatures that have not been found by human.