Giant FRESH-WATER Stingray! The giant stingray is one of the world's largest freshwater fish, but it's also cloaked in mystery. No one is sure how many giant stingrays are left, which habitats they prefer, or even if they ever venture into the ocean, where their more commonly known relatives dwell. These ancient fish, little changed over many millions of years, can reach 16.5 feet (5 meters) long and weigh up to 1,320 pounds (600 kilograms).
How exciting! The newly discovered arapaima, named Arapaima leptosoma, is the first new species described since 1847. Arapaima, one of the world’s biggest freshwater fish and the largest freshwater fish of South America, is unique among fish – it can breathe air. The largest specimens can reach more than 2.5 m in length and weigh up to 200 kg.
The arapaima, a giant Amazon river fish that can grow longer and heavier than a human adult, is at risk of extinction, according to a new study. Overfishing and errors in classification are believed to have left the world's largest scaled freshwater fish critically endangered.
The wallago catfish occurs in freshwaters from Pakistan to Vietnam, Hogan said. The wallago catfish is a large, predatory catfish, attaining lengths of up to 7 feet. In India, the species is threatened by over-harvest, habitat degradation, and pollution