Goldfish, the most pitiful fish on our planet
In the life of the inhabitants of the mainland, the most familiar fish is probably the goldfish. This colorful aquarium fish can add beauty to your room. However, if you try to find this fish in the wild, you will probably encounter repeated disappointments, because they are a man-made species.
And it’s also because the individual species that created many of the fish’s characteristics has disappeared from them, and that’s also the reason why even if they are released into the wild, they can’t live.
In fact, from foods to pets, there are few creatures as radically transformed by humans as goldfish. They have been selected and re-created over the centuries solely to serve our desires, preferences, and fantasies. From the ordinary and dull fish of the past, it has evolved into creatures with colorful, varied, even deformed bodies.
Many people believe that the ancestors of goldfish are carp or fish, however, the only thing in common between them is just gentleness. In fact, the ancestors of goldfish are wild carp.
As early as 1928 to 1934, professor Chen Zhen in China discovered a truth in goldfish breeding experiment: any type of goldfish can be crossed with wild carp and give birth to golden carp. fertile offspring. This experiment demonstrated for the first time that there is no reproductive isolation between goldfish and carp, and that they are very closely related. The scientists then conducted further studies such as comparative embryonic development and karyotype analysis to show that the goldfish was originally the Chinese carp. Taxonomically, goldfish are not a separate species, instead they are grouped with the carp (Carassius auratus).
So what is the factor that makes the carp turn into a goldfish? The answer of species evolution is “gene mutation, natural selection”, while goldfish evolution is “gene mutation, artificial selection”. This is exactly the same as raising a regular pet dog, but the breeding and breeding of human goldfish is somewhat more extreme. After hundreds of years of selection by the Chinese, the goldfish has lost all of its physical features. From body color, body shape, head shape, eye shape, scales, back, tail, anal fin,… they have basically changed completely and have a completely different appearance compared to carp.
The most primitive mutation in the evolution from carp to goldfish occurred in body color. In the multitude of ordinary carp, occasionally a yellow carp with a striking color will appear. According to the available historical data, the earliest record of these mutant fish is in the Jin dynasty of China (AD 265-420), 1,600 years ago.
However, at that time, people thought that these were special creatures, possibly related to spiritual elements, so whenever they caught them, they often took precautions to give birth and considered it a good deed. accumulate virtue for future descendants. During the Tang Dynasty, this practice continued, but at this time, people built special release ponds (in the release ponds there are other creatures such as turtles and golden carp…), according to which Yellow carp that are accidentally caught in the wild are also released there and make them semi-domesticated.
Over time, people began to build lakes just to raise golden carp and golden carp for the purpose of entertainment, raising as an ornamental. It was not until the Song Dynasty that the officials of the Chinese court began to artificially breed goldfish. Since then, some dignitaries have also imitated, set up their own gardens as fish ponds, and enjoyed watching fish. Wild carp has since entered a state of domestication. In order to avoid crossbreeding with natural carp in stocked ponds, fish with 3 colors of yellow, white, silver and green have been selected for separate rearing.
Of course, not everyone can afford to keep fish in a large pond. Ordinary people who wanted to catch up with the trend started making pots and tanks and started raising goldfish on a large scale. During the Ming Dynasty (1546), private goldfish farming became very popular.
Accordingly, this is truly the most important turning point in the history of goldfish domestication. The shape of the goldfish has undergone tremendous changes since this time. Due to the pressure of the potted habitat, the physicality of the goldfish has also changed, while indirectly affecting heredity through artificial selection.
In the wild, in order to swim quickly to avoid predators, find food…, the body shape of fish will almost be elongated. But in a small tank, the maneuver space of the goldfish is extremely limited, so it can only swim slowly. Under human protection, they not only avoid the pursuit of natural predators, but also increasingly rely on artificial food sources. Therefore, the newly created genetic variation is more likely to be preserved under careful human care.
At that time, the ancients knew how to selectively and purposefully breed individuals that were adapted to life in small tanks and pots. And this artificial selection also promotes the evolution of the whole body of goldfish, while forming many different new strains.
In just a few hundred years, the long, flat body that was suitable for fast swimming has become a short, round body. The original straight singletail has also evolved into a long and broad fork, and some caudal fins become multi-lobed; some have protruding blisters; some had large head tumors on the top of their heads… Darwin in his book “Variations of Domesticated Animals and Plants” described that there were “no less than 89 varieties” in China at that time.
After the Qing Dynasty, business-minded fish farmers began to consciously conduct artificial breeding and choose the direction of goldfish. Also during this golden age, goldfish were introduced to Japan in waves, and then to European countries at the end of the nineteenth century. Almost all goldfish varieties in the world today are of Chinese origin. Therefore, goldfish is also known as the “holy fish of the East”.
At present, there are more than 300 varieties of goldfish in China. Although some characteristics like body color are neither beneficial nor harmful for survival. But it is not difficult to see that the vast majority of mutant goldfish are not able to survive in the wild.
For example, the short, round body shape and various fancy tail shapes are not conducive to goldfish swimming. In particular, the variation of the tail type is divided into nearly a dozen types, including single tail, double tail, single upper double tail (three tails), vertical tail, fan tail, butterfly tail …
The lack of a dorsal fin, a typical feature of the egg goldfish, makes it easy to lose balance and will become disoriented when swimming too vigorously.
Their short, stout body makes them susceptible to bladder disease and high mortality.
The different types of head tumors are essentially thin layers of epidermal cells that continuously divide and proliferate, filled with loose connective tissue and mucus. But whether it is a high head, a dragon’s head, a tiger’s head, a lion’s head, a goose’s head… all are “burdens” for the head and gill cover, and also affect the respiratory process of fish. yellow. Therefore, cannot bear the impact of strong water currents.
As long as it is under careful human care, these deformed features will not affect the survival of the goldfish. They only need to be quietly in the water, in addition to eating or swimming, their genes can be preserved and passed on from generation to generation. Goldfish are bred to bring happiness to humans, and humans give them a “superior” life compared to wild species. However, many goldfish have too many body variations, making them very susceptible to sudden death. And people always crave new things, so what the future of goldfish is like, their upcoming changes, perhaps few people can accurately predict.
at Blogtuan.info – Source: cafebiz.vn – Read the original article here