Old man fish new fish home to go through the water, home to the fish even the confetti bag together in the tank soak 1 hour will not be easy to die, in fact, the old man fish in fact, is also relatively easy to live, just catching a disease infection is not easy to survive.

There are about 32,000 species of fish in the world that have been discovered, and the fish live in the water, distributed in the ocean and freshwater, living in the ocean accounted for two-thirds of the rest live in freshwater.

From a variety of fish meat can be extracted hydrolyzed proteins, cytochrome C, lecithin, ceruloplasmin, etc. The liver and ovaries of puffer fish contain a large amount of tetrodotoxin, which can be extracted to treat neurological disorders, spasms, tumors and other diseases. The bile of large fish can be extracted "bile pigment calcium salt", for the artificial manufacture of raw materials of oxalic acid.

The difference between the fish is as great as that between the terrestrial vertebrates. Fish are generally considered to be smooth-bodied, spindle-shaped, streamlined, finned, gill-breathing aquatic animals, but many more species do not fit this definition.

The shape and position of the mouth, eyes, nostrils, and gill openings are extremely variable. Fish are an important food for humans. Overfishing, pollution, and environmental changes can destroy fish stocks, and fish predation, which helps control mosquito-borne diseases such as malaria. Fish are important laboratory animals for behavior, physiology, ecology and medicine.