When I was a child, I wondered if the fish should drink water? 5

1. Fish that live in freshwater do not drink water for the rest of their lives. This is because of the osmotic pressure relationship. Osmotic pressure is formed by substances dissolved in water.

The more material dissolved in the water, the higher the osmotic pressure. Fish contain a lot of salts and proteins in the blood and tissue fluids, and the concentration of the solution is higher than that of the surrounding fresh water, and the osmotic pressure is also higher than that of fresh water. Since the water is from a solution with low osmotic pressure to a solution with high osmotic pressure.

As a result, the surrounding freshwater seeps into the freshwater fish from all directions. As a result, not only do these freshwater fish not have to drink water, but they also have to find ways to get the excess water out of their bodies, otherwise they will be swollen to death by the water. 2. Fish living in the sea need to drink water frequently.

Because the salt content in seawater is much higher than that in the body fluids of these fish, the osmotic pressure in seawater is also much greater than in the body of fish.

The sea desperately sucks the water from the fish, so that these fish have to drink water frequently. But there are also fish that don't need to drink water. Sharks, for example, don't drink water.

The shark is a cartilaginous fish, it does not have a gill cap, but has 5-7 gills on the back of the head, the gills are in this, and the shark has many capillaries on its body, which absorb oxygen directly from the water and emit carbon dioxide. And it has to swim non-stop, and the cleft cheek can keep approaching the large amount of seawater containing fresh oxygen and breathe constantly. In fact, whether most marine fish need to drink water, or freshwater fish and a small number of marine fish do not drink water, they are all for their own needs.

If they don't meet these needs, they will definitely die of maladaptation to the environment.

01 The main components of fish blood and body fluids are salt and protein, and when living in fresh water, the concentration of water is much lower than that of fish body fluids, and the osmotic pressure is higher than that of water. So freshwater fish do not need to drink water throughout their lives, while marine fish have to drink water frequently.

Humans generally only live for three days without drinking water, but fish will die ten minutes after leaving the water, and all brothers can only live in water. Sometimes we may have this question: the fish lives in the water every day, does it drink water, and how much water does it drink in a day?

If I drink too much water, will my stomach swell?

In fact, fish are divided into freshwater fish and marine fish, of which freshwater fish do not need to drink water throughout their lives, while marine fish must drink water regularly. The secret here is that the salt content of the water is different.

The main components of fish blood and body fluids are salt and protein, when living in fresh water, the concentration of water is much lower than that of fish body fluids, and the osmotic pressure is higher than that of water, and the characteristics of water flow from the place of low osmotic pressure to the place of high osmotic pressure, so the water around the fish will desperately penetrate into the body of the fish. Therefore, instead of drinking water, the freshwater fish we see need to continuously excrete excess water in the form of urine through the well-developed kidneys to ensure the osmotic balance in the body.

The opposite is true for fish living in seawater, where the concentration of body fluids is constant, and the only variable is the concentration of water. The concentration of seawater far exceeds the concentration of fish fluids, so the osmotic pressure is the opposite of that in freshwater, and the fish fluids are constantly pumped into the sea. Therefore, the fish in the sea must drink water constantly, otherwise they will soon lose blood and die.

It is precisely for this reason that the kidneys of marine fish generally become well-developed, so that they can be metabolized through the gills in time when a large amount of seawater is inhaled.

In fact, when the fish inhales the water, the gills also absorb the oxygen in the water through the gill filaments. We now know that most of the gill filaments of fish are composed of capillaries, and the inhaled water will flow in the direction of the gill filaments, and in this process, the oxygen is "intercepted" by the gill filaments, so the fish's mouth is closed together and looks like drinking water, but in fact it is just getting oxygen.

Not only do all freshwater fish not drink water for life, but the fish also have to try to remove too much water from the body frequently, otherwise the fish will be "swollen to death", because the water will penetrate into the fish body from all directions, through the epidermal tissue of the fish, so the freshwater fish do not need to drink water at all.

Yes, there is no energy supply for the body to move without eating, so the fish will be.

No, I used to fish for two and a half years and didn't die, just drink water, eat a steamed bun and hang up.

Fish in the river in winter in deep water.

If the water is relatively wide, the fish want to winter, most of the water color is darker and turbid, even if the winter activity is poor, but it is not motionless, the fish will gather together to have a sense of security, so at this time the water body is turbid most likely to have fish underwater. In winter, the temperature is relatively low, and the fish tend to be in some sunny places. Fish basically don't like to swim around, so you can choose some sunny places, ** the high water temperature, the more activities the fish will be.

The temperature of the water is related to the density of the water, and at a certain temperature, the deeper the depth, the higher the water temperature. Of course, at the same depth, the higher the temperature, the higher the water temperature.

4 degrees Celsius water is the most dense, so 4 water is at the bottom and 0 is the same as ice, and at the top is deeper. Therefore, as long as the pond is not completely frozen in winter, the fish can survive, and the fish can move in the water for 4 years.

This is determined by the specific way the fish breathe.

Because the fish breathes with its gills, and at the same time, the gills can only absorb the oxygen dissolved in the water, but not the oxygen in the air, so if the fish leaves the water, the body of the fish cannot replenish the oxygen, so the fish will die when it leaves the water.

As a result, aquatic vertebrates, like animals living on land, cannot do without oxygen, but fish do not have lungs and can only rely on their gills to draw oxygen from the water, while amphibians have both lungs and gills and can land. You also have to know that fish are the ancestors of land animals, in the distant past, there were only aquatic animals on the earth, and then some fish evolved lungs, which are amphibians, and then further evolved before they completely left the water to live on land, and gradually evolved to reptiles, vertebrates.

First of all, fish breathe by gills, and gills must be kept moist, when the gills are exposed to air, they will dry out, and the surface area will also shrink, which is not conducive to breathing, while in the water they can stay moist and can breathe normally to take in the dissolved oxygen in the water.

Secondly, it is not the same as relying on the movement of the fins and body in the water, but on land, these two are useless, and they are easily attacked by natural predators.

Therefore, it is in the water (it is not excluded that mudskippers, lungfish, etc. often come ashore).

Fish can't live without water. Fish live in the water this is a natural law, is people know common sense, then, fish.

Why live in the water and can't live without it?

This is mainly determined by the respirator tubes and breathing patterns of the fish itself.

Fish have the characteristics of being suitable for living in water: the color of the body of the fish is the protective color of the fish. The body is streamlined, large in the middle and small at the end.

The surface of the body is covered with scales, which protect the body; There is a layer of mucus on the surface of the scales, which reduces the resistance of the water when swimming. There is a lateral line on both sides of the body, which is connected to the nerve, which is mainly used to determine the direction and sense the flow of water. The body of a fish has pectoral fins, dorsal fins, pelvic fins, and caudal fins, which are the locomotor organs of the fish in the water.

Fish breathe with gills. There is a swim bladder in the body, the main role is to regulate the specific gravity of the body, the swim bladder in the coordination of the fins, can make the fish stay in different water layers.

Fish belong to the lower animals of vertebrates because they cannot live without water all their lives, breathe with gills, heart-atrium-ventricles, a circulatory route, and arterial and venous blood are mixed; In particular, the reproduction of fish is naturally hatched by in vitro fertilization, and the body temperature is not constant.

The role of the fin: The dorsal and anal fins mainly play a stabilizing and balancing role when moving. The tail fin works with the muscles on the side of the body to propel the fish and control the direction.

The main function of pectoral and pelvic fins is to maintain the balance of the fish, cooperate with the body of the fish, and adjust the lifting of the fish. However, pectoral fins are more versatile than pelvic fins, and they can be used like oars to move the fish forward slowly.

Because the gills of a fish are only adapted to absorb oxygen from the water and cannot absorb oxygen from the air, it can only live in the water.

I don't have lungs, I can't breathe air.

Fish are in the water because of their characteristics, which are the way of survival given to it by nature.