Do fish have eyelids, do fish have eyelids, why do fish not have eyelids

Fish don't have eyelids, so they can't blink; Fish eyes are not afraid of salt water and are kept moist at all times, so they don't have to moisten their eyes with tears. But the exception is the crocodile, which has transparent eyelids.

Although fish belong to the lower vertebrates, the structure of their eyes is similar to that of the human eye. The difference is that the lens of the human eye is oblate and round, allowing you to see things in the distance; The lens of the fish's eye, on the other hand, is spherical in shape, and only close objects can be seen. All fish are short-sighted, and they rarely see objects up to 12 meters away, which is related to the fact that the curvature of their lenses cannot be changed.

However, although the fish is short-sighted, they are very responsive. Anglers often find that when he walks to the river and has no time to put down the hook, the fish has already noticed it and quickly escaped.

It turns out that although the fish does not see far in the water, it is able to see objects on land in the water through the refraction of light. As a result of refraction, the fish perceives objects on land to be much closer and higher than they actually are, so that before the person is near the water's edge, it feels that the person is above its head. Therefore, experienced anglers usually squat on the shore so that the human body is at a minimum angle to the water level, so that the fish cannot see the person.

In general, fish have a much wider field of view than humans, so they can see objects in front of and behind and above without turning around, for example, freshwater salmon have a field of view of 150 degrees in the vertical plane and 160 170 degrees in the horizontal plane, while the human eye has a field of view of 134 degrees and 154 degrees, respectively. It is for this reason that the ultra-wide-angle lens used on the camera is also known as a fisheye lens.

Fish do not have eyelids. This animal lives in water and does not need eyelids to keep the eyeballs moist, and it also does not need eyelids to protect the eyes. However, sharks have eyelid-like membranes or folds that allow them to protect their eyes when hunting.

Fish do not have well-developed vision and can see near objects clearly, but they can sense the position of the fish around them through the lateral line, which is convenient for them to hunt. For fish, the eyelids are not needed to keep the eyes moist, and at the same time, they will not encounter some sand and dust in the water to cause it to be blind, so the eyelids are useless. However, the shark has an instantaneous membrane or instantaneous fold similar to the eyelid, which allows it to cover its eyes when attacking, thus avoiding eye injury.

Yes, I have raised a few small fish (all of which are of different species) before, and they are mixed with turtles, but in fact, turtles do not eat fish. I looked closely, and they had green eyelids and blinked from time to time. At that time, I told my grandmother, and my grandmother was confused and said that her eyes were hairy, and my aunt also knew that fish had eyelids, but fish really didn't have eyelashes.

I don't know why I sleep with my eyes open, because I've never seen a fish sleep. Please don't believe those ignorant people who just use esoteric language to make everyone believe that there are some things that you still have to observe and find out for yourself.

Fish do not have eyelids, and their eyes often need to be lubricated by the surrounding water, so fish do not blink, but can only keep their eyes open forever, and sleep with their eyes open; Even when you die, you can't close your eyes - you can really call it "dead without blinding". Fish have no eyelids, their eyes often need fish are without eyelids, their eyes often need to be lubricated by the surrounding water, so fish do not blink, fish have no eyelids, their eyes often need to be lubricated by the surrounding water, so fish do not blink, they can only keep their eyes open forever, and they sleep with their eyes open; Even when you die, you can't close your eyes - you can really call it "dead without blinding". I can always keep my eyes open, and I sleep with my eyes open; Even when you die, you can't close your eyes - you can really call it "dead without blinding".

It is lubricated by the surrounding water, so the fish does not blink, but can only keep their eyes open forever, and sleep with their eyes open; Even when you die, you can't close your eyes - you can really call it "dead without blinding".

Ordinary fish have no eyelids, because of the structure of their eyes, in fact, the eyes of fish are very similar to human eyes, but the difference is that the crystal of fish eyes is round, and only relatively close objects can be seen. Therefore, fish meat is like myopia, it is usually difficult to see distant things, and fish meat does not blink, so fish meat does not have eyelids.

Ordinary fish do not have eyelids, because of the structure of their eyes, in fact, the eyes of fish are very similar to human eyes, but the difference is that the lens of fish eyes is spherical, and only close objects can be seen. Therefore, the fish is like a short-sighted person, generally unable to see things in the distance, and the fish cannot blink, so the fish has no eyelids.

The fish doesn't have eyelids, it's in the water, and it's the kind of group that has to survive in the water, so it doesn't have eyelids.

Fish have eyelids, but because of adaptation to the living environment in the water, and a long time to evolve, the eyes of the fish will always be open, will not blink like some animals or humans, if you like fish, you can buy a few cute little goldfish and keep them in bottles.

This question is really difficult to answer, from a physical point of view, fish live in the water all their lives (the stage of leaving the water is basically negligible), the fish's eyes and the water have a certain pressure balance, and if there are eyelids, when the eyes are closed or opened, this pressure balance will be broken and unnecessary damage will be caused.

Translate the person who suddenly became Du Fu's happiness.

Because the fish is stupid, it is ok to understand and understand.

Fish do not have eyelids, the main function of eyelids is to moisten the eyes, and at the same time provide protection, fish live in water, so they do not need eyelids to moisten the eyes, a few fish have an instantaneous membrane similar to the eyelids, which can play a role in protecting the eyes. These animals generally have fins, which are divided into pectoral fins, pelvic fins, anal fins, dorsal fins, and caudal fins, which allow the fish to swim and maintain their balance at the same time. <

Fish do not have eyelids. The eyelids, also known as the eyelids, have two functions, one is to protect the eyes, and the other is to moisten the eyes by turning them. Fish themselves live in water and do not need to moisten their eyes, so they do not need eyelids much.

However, some sharks have eyelid-like membranes or folds that allow them to protect their eyes when hunting.

1. Pectoral fin: The pectoral fin grows behind the gill cover, and for fish, the role is similar to the forelimbs of land animals, which can play a role in balancing and mastering the direction when it swims, and can maintain balance when it stops. If the speed of swimming is slow, the pectoral fin acts like a paddle and is attached to the body when moving at height to be able to slow down and brake.

2. Pelvic fin: If the pectoral fin is the forelimb, then the pelvic fin is similar to the hind limb of a terrestrial animal for fish, which is used to assist the dorsal fin and anal fin to maintain balance, and at the same time help the fish to rise and fall, as well as change direction. Usually the pelvic fins are not born in a fixed position, some are ventral, some are in front of the pectoral fins, and some feed the larynx between the gill covers.

3. Anal fin: The role of the anal fin can coordinate the fins of each fish, if not, the body of the fish will shake slightly.

4. Dorsal fin: The dorsal fin can keep the fish upright, which plays an extremely critical role in balance, and it is easy to roll over if you lose it. In addition, for some fish with longer body lengths, the dorsal fin can also play a role in propelling forward.

5. Tail fin: The tail fin is particularly important for fish, which can not only determine the direction of movement, but also provide power.

Fish don't have eyelids because they don't need eyelids. The eyelids have two functions for terrestrial animals, one is to moisten the eyeballs and the other is to protect the eyes, and for fish, since they live in water, they do not need eyelids to moisten the eyes.

And there is no sand and dust in the water to get into the eyes, so there is no need for eyelids to protect them. However, some sharks have eye-like membranes that cover their eyes when they hunt.

Summary. The main reason for the upper and lower eyes of the fish is the environment, and the fish tank will generally raise the tank seat to facilitate viewing. The visible surface of the fish tank body, including the front and back, left and right, above and the bottom of the tank, usually the moving things on the ground will always attract the attention of the Arowana, and then produce actions such as looking for things in the tank, and over time, the phenomenon of downward vision will naturally appear, and cause the accumulation of fat in the eye socket.

The main reason for the upper and lower eyes of the fish is the environment, and the fish tank will generally raise the tank seat to facilitate viewing. The visible surface of the fish tank body, including the front and back, left and right, above and the bottom of the tank, usually the moving things on the ground will always attract the attention of the Arowana, and then produce actions such as looking for things in the tank, and over time, the phenomenon of downward vision will naturally appear, and cause the accumulation of fat in the eye socket.

Lay bottom sand at the bottom of the tank to avoid the bottom of the tank reflecting the Arowana's own shadow, chasing the shadow of the bottom of the tank, causing downward vision and forming upper and lower eyes.

Summary. Dear Hello I'm glad to answer the reasons for the fish's upper and lower eyes: First, the physiological structure of the fish makes it possible for them to have a cross blind spot in front of their eyes, and the circular container is not visible in front of the fish, so they swim all the way to the surface of the water.

The second is that the lone glass refracts light into the water, which will cause damage to the vision of the fish, resulting in an increase in the internal pressure of the fish's eyes, and eventually the death of the swim bladder. The third is that the small round tank does not have a filtration system, the water is not changed frequently, and the water quality deteriorates, resulting in fish eye lesions.

Dear Hello I'm glad to answer the reasons for the fish's upper and lower eyes: First, the physiological structure of the fish makes it possible for them to have a cross blind spot in front of their eyes, and the circular container is not visible in front of the fish, so they swim all the way to the surface of the water. The second is that the lone glass refracts light into the water, which will cause damage to the vision of the fish, resulting in an increase in the internal pressure of the fish's eyes, and eventually the death of the swim bladder.

The third is that the small round tank does not have a filtration system, the water is not changed frequently, and the water quality deteriorates, resulting in fish eye lesions.

Pro, the main reason for the fish eyes up and down is the environment, and the general fish tank will raise the tank seat to facilitate viewing. The visible surface of the fish tank body, including the front and back, left and right, above and bottom of the tank, usually the moving things on the ground will always attract the attention of the Arowana, and then produce actions such as looking for things in the tank, and over time, the phenomenon of looking down will naturally appear, and cause the accumulation of fat in the eye sockets. There is a way to delay the downward vision of the eyes, and the first thing to do is to improve the breeding environment

1) Lay the bottom of the tank with bottom sand to avoid the bottom of the tank reflecting the image of the Arowana itself, chasing the shadow of the bottom of the tank, causing the downward view (2) The visible surface of the left, right and back of the fish tank is covered with opaque background paper, and the visible surface and a downward view surface are retained. (3) Lower the water level by 10-15 cm, so that the Arowana can increase the visible surface on the water surface. (4) Try to feed floating fish food, including floating feed, insects or animals, and feed fish and shrimp with single and double feeding, so that fish can bite in pelagic waters.

5) Choose a two-eyed flat feeding as much as possible.