As the hometown of catfish, Oujiang River was once brilliant. In the 1950s, giant salamander was very common in Oujiang waters, and people in the city were proud of it. According to the investigation of Institute of Hydrobiology, Chinese Academy of Sciences, the resources of giant salamander in Oujiang River are still considerable in 1966. During the Cultural Revolution, giant salamanders appeared on the Oujiang River, which almost wiped them out. On the one hand, due to the cold fishing and overfishing of human beings, the resources of giant salamander in Oujiang River are increasingly scarce and become rare aquatic creatures. On the other hand, due to the need of construction, a large number of sand and gravel were excavated, which destroyed the spawning ground of giant salamander; The increasingly busy shipping industry and serious water pollution in the Oujiang River have also brought great threats to the survival of the giant salamander, thus making the "general" family decline day by day.

The largest freshwater turtle, Japanese catfish, is also called sand turtle, blue grouper and green grouper. It is the largest kind of freshwater turtle, with a body length of 80- 120 cm and a weight of about 50- 100 kg, the largest of which exceeds 100 kg. The appearance is very similar to the common Chinese soft-shelled turtle, which is covered with soft skin and has no horny shield like a turtle. The back and abdomen are covered with bone plates, which are connected left and right to form a special "armor", but they are also different from the Chinese soft-shelled turtle in many aspects. In addition to its large size, its snout is very short, not as long and sharp as the Chinese soft-shelled turtle. Its head is blunt, wide and flat, its nostrils are small, and it is located in the snout, which is short and not prominent. The body is flat, round, flat and thin, the back is flat, and the back nail is not convex, showing a plate shape. The anterior edge of the base of the neck and the dorsal nail is smooth, and there are tumor-like processes at the back. The back is brownish yellow or brownish green, the head and abdomen are grayish yellow, the tail and hind limbs are grayish yellow, and there are rusty yellow patches on the ventral surface of hind limbs. The toes of the third and fifth toes have claws, and webbed toes is bigger. The anus is grayish black.