Look! How interesting this fish looks: its body is flat on its side, but it has a pair of big and prominent eyes on its head, which can rotate flexibly in all directions. Its name is mudskipper.
This kind of fish generally lives on the tropical coast and the southern coast of China. Whenever the tide ebbs, you can see them jumping on the wet beach and sometimes climbing to the roots of mangrove trees. Although the mudskipper has no feet, it can climb and jump, mainly because its pectoral fins are very thick, like the forelimbs of land animals, and move freely. Its ventral fins are merged into a sucker, and when it climbs to the wet muddy ground, it can be adsorbed on other objects by the sucker. The walking action of the mudskipper on land is very interesting: it supports its body with its ventral fins first, and then moves forward alternately with its pectoral fins. At first glance, everyone thinks that the action of the mudskipper is very slow. If it encounters enemy harm, its crawling speed is quite amazing. It will also use its tough pectoral fins, sharp teeth and wide mouth to dig a big earth hole, and it can hide in the hole to escape the heat in hot summer. The gill cavity of mudskipper is very large, which can store a lot of air. At the same time, the skin of this fish is covered with blood vessels, which plays an invisible role in assisting breathing. When it moves on land, it often sticks its tail fin into a weedy puddle or clings to wet mud. This can also help breathing. Bullet fish like to eat small crustaceans and insects, and their meat is delicious and tender, with high nutritional value.
In Fujian, Guangdong and some tropical and subtropical lakes and marshes in China, there is a small fish, which likes to hunt at night. They always leave the river in droves and go through the fields to the road to find their favorite insects. Sometimes they find small insects in the bushes, so they jump up and climb back into the river after eating enough. This kind of fish that can live without water is called climbing bass.
The action of climbing bass is very strange. There are many hard spines behind its gill cover. Whenever it moves, it leans against the ground with the help and cooperation of pectoral fin and tail, and it can crawl forward bit by bit. In the dry season, perch climbing can live in wet mud for several months without starving to death, and it will not die because the river dries up. This is because the perch also has a secondary respiratory organ, which is behind its gill cavity and has folds similar to the shape of fungus, and the surface of the folds is covered with many capillaries, so that gas exchange can be carried out.
There is also an eel that looks like a snake. Besides living in water, it often climbs to wet grass or places where rain flows to find food. It likes eating small insects and snails very much. Whenever they are full, they crawl around in the grass on the shore, and sometimes people who walk are startled by eels. Eel's body is covered with mucus, and the scaleless skin is covered with microvessels, so that the skin can be used for gas exchange with the outside world to maintain life. However, some people think that the main reason why eels can live without water is that the gill holes of this fish are very small, so the water is not easy to evaporate. We say this view is incorrect. Monopterus albus is a well-known freshwater fish, and its meat is very tender. Monopterus albus generally lives in shallow water places such as ponds and rice fields. Some people often see Monopterus albus erect its front half and look around. In fact, it has nothing but is breathing fresh air. Through observation, the gill of Monopterus albus has been degraded for a long time, which gives it a big problem to breathe in the water. However, the surface of the mouth and throat of Monopterus albus is covered with microvessels. It can stick its head out to swallow air into the mouth and exchange oxygen slowly, so it will not starve to death after spending several months in the mud.
In addition, lungfish, loach, mullet, etc. also belong to fish that can live without water. As mentioned just now, most fish have a set of skills to survive without water. These skills are scientifically called having accessory respiratory organs.