The eyes of fish see things in the water in the same way that we humans see things in the air. The color of the fish's hair is completely determined by their mood, and the mood comes from the observation of the surrounding environment by their eyes. The mystery in the eyes of fish, you know?
We humans are "three primary color organisms", that is, we only have three kinds of cone cells in our eyes, so we always say three primary colors: red, yellow and blue. Compared with other animals, especially fish, visible light is very limited. Fish have four types of cone cells, that is, the fish's eyes have four independent channels for color information transmission. Even some fish can see much shorter light in the near ultraviolet spectrum than in the light waves visible to humans.
What does it mean that fish are superior to human vision?
As ordinary ornamental fish lovers, we have to admit that sometimes we look at certain species of fish, and their appearance seems to be similar, and even often confuses them. However, in the eyes of the fish, to identify whether it is the same species of fish as yourself, you only need to scan the eyes for a moment to confirm the look in your eyes. Because in some fish face or other parts of the body, there will be dot-like and curved patterns similar to human fingerprints, which can only be seen with the naked eye under ultraviolet radiation, and fish can be easily recognized without the help of ultraviolet light.
Brightly colored marine fish
In 2010, scientists conducted an experiment involving two very similar-looking species of snapper living in coral reefs in the western Pacific Ocean, namely the Ambon snapper and the Moluga snapper. The Ambon snapper has a strong sense of territory, but they only drive away their own kind, and they can still get along with other species of fish. This fish uses its own unique visual facial pattern in the ultraviolet spectrum to identify whether the intruder is its own kind.
In order to better verify the experimental results, the researchers also used photos of their kind to identify the fish, which they could also recognize and receive food as a reward. When the researchers removed this visual information with a UV filter, the Amber crested seabream was very difficult to pass the test, which also better proved the results of this experiment.
If you are a friend who often watches the fish in the fish tank at home, it is easy to find that the fish will not close their eyes when they sleep, because they do not have eyelids like humans. In addition, the eyes of fish are very similar to those of humans, as well as most vertebrates, and are controlled by three pairs of muscles, which can flexibly rotate in different directions with the help of suspensory ligaments and muscle contractions.
Although fish do not have eyelids and eyelids, nor do they have lacrimal glands, they cannot keep their eyeballs moist by blinking like humans or other vertebrates. However, the water environment in which fish depend is enough to help clean and moisturize the eyes.
Flounder with two flexible eyeballs
Some fish can even see two worlds in their eyes, which is a visual height that we humans can't reach anyway. Everyone should know that chameleons, their two eyeballs can be distributed and rotated in different directions, which means that one eye can stare at the prey for hunting tasks, while the other eye can observe the surroundings to see if there is any danger. Similarly, hippocampus, gobies and flounders have the same eye muscle tissue.
Here we have to use the Chinese fighting fish that we are most familiar with, the Chinese fighting fish has another name, called the cover spot fighting fish, the origin of this name is precisely because their two sides of the gills have a very bright spot, these two spots look very much like the eyes. The reason why it grows so much is also to protect the real eyes in the body.
The importance of fish eyes is equal to the importance of human eyes, and blindness is a very useful skill in the process of fighting. Similarly, while the belligerent fish fight, the attacking side will also give priority to attacking the opponent's eyes. So we will also see one-eyed fighting fish from time to time, which is the trace of the fight. In the evolution of the generation, in order to protect the real eye from harm, the fighting fish is near the eye, and then derives another pair of "eyes", which are used to confuse the opponent.
Typical Chinese Fighting Fish (Covered Bucket Fish)
Other fish even have multiple pairs of prosthetic eyes, and some fish even camouflage the prosthetic eyes and heads in the tail. After all, it's better for an predator to bite off a small piece of tail than to be bitten off on the head and eyes.
Ornamental fish hair color is the pursuit of each of us to raise fish, but why do fish show different body colors, do you know? In fact, a variety of different colors of body color, are the expression of fish self, we mentioned earlier, the fish's eyes have four kinds of cone cells, so the color recognized is much more than humans, that is, the information transmitted through body color is far greater than our inherent cognition. The same kind can transmit important information about gender, age, fertility status, and mood through body color. The pigment cells inside their skin contain carotenoids and other compounds that exhibit a variety of warm colors.
When we see a fish with a body color whitish, it is not caused by the lack of pigment, but the visual result of the uric acid crystals in the white pigment cells and the guanine reflection fibers in the rainbow cells. In addition, there are many color secrets in the fish scales, the common green, blue and purple are mostly formed by the fish skin and the structure in the fish scales, and different thicknesses can show different colors.
So, when you see a fish with a lighter body color, it is likely to tell you that I am in a very bad state now, or that I am in a very unhappy mood. When a fish's body color is darker, it tells us more that it is excited or in great shape. And all these body color changes are based on the fish's eyes' observation of the surrounding environment, feedback to the body, and then the body color of the body shows multiple changes. Most fish can disguise their body color like chameleons to resemble their surroundings, but they can't do that if they blindfold them.
West African birdfish of paradise who was excited in the mirror
The above is some of the mysteries about the fish eye, hoping to help everyone better understand the ornamental fish in their own fish tank. Only by better understanding them is it more likely to raise them well.
If you also like to raise ornamental fish, you may wish to start pointing out a point of attention, all you need to know about fish farming is here.