It's a ray.

Rays, also known as laobanzi, labori, fu fish, cartilaginous fish. It is the collective name of the order of skates and the family of skates, and there are about 380 species in the world, with 38 species in China, which are widely distributed in the sea areas of the three oceans, and are also found along the coasts of China.

Morphological features:

Flat body, long and slender tail, some species of skates have one or more venomous spines with serrated edges. The eyes and spouts grow on the top of the head, and the mouth, snout, and gill slits are on the bottom side, all of which evolved gradually as the skate adapted to benthic life. The teeth are like stone molars, capable of grinding anything, and a highly poisonous red spine grows on the back, which can kill a human being when stabbed. A fan-like circle of pectoral fins grows around the ray's body, and the tail fin degenerates to resemble a long, thin whip that moves forward in a wave-like motion on the pectoral fins.

Expanded Information

Habitat:

An offshore demersal fish, often lying on the bottom of the sea or buried in sand and mud. Sometimes also creeping on the seabed or offshore swimming, swimming mainly by pectoral fins fluctuation back and forth, slow action, lurking in the daytime, night feeding, mainly to small crustaceans, polychaetes, mollusks, small fishes and cephalopods, etc. for food. Oviparous, the eggs are covered with a quadrangular horny shell, which can be developed by the protrusion of the four corners of the sticking to the attachment, usually spawned in batches every few days, each time the spawn of 2 grains.

Baidu Encyclopedia - Rays