In the lives of mainland residents, the most familiar fish is probably goldfish. This colorful ornamental fish can beautify your room. However, if you try to find this fish in the wild, you will likely encounter constant disappointment, because they are an artificial fish. And it is because of the individual species that many of the characteristics of fish have disappeared in them, and that is also the reason why even if released into the wild, they cannot survive.

In fact, from foods to pets, few creatures have been transformed by humans as thoroughly as goldfish. They have been selected and re-created over the centuries solely to serve our desires, preferences and fantasies. From the normal and dull fish of the past, it has evolved into creatures with bright colors, diverse bodies, and even deformities.

This colorful ornamental fish can beautify your room.

Many people believe that the ancestors of goldfish are carp or cai fish, however, the only thing they have in common is their gentleness. In fact, the ancestors of goldfish are wild crucian carp.

As early as 1928 to 1934, professor Chen Zhen in China discovered a truth in goldfish breeding experiments: any type of goldfish can be crossed with wild crucian carp and produce new animals. Females are capable of reproducing.

This experiment demonstrated for the first time that there is no reproductive isolation between goldfish and crucian carp, and that they are very closely related. Later, scientists conducted further studies such as comparing embryonic development and karyotype analysis to show that the original goldfish was the Chinese crucian carp. Taxonomically, goldfish are not a separate species, instead they are placed in the same species as the crucian carp (Carassius auratus).

Crucian carp

So what is the factor that makes crucian fish turn into goldfish? The answer of species evolution is “gene mutation, natural selection”, while the evolution of goldfish is “gene mutation, artificial selection”. This is exactly the same as raising regular pet dogs, but human breeding and breeding of goldfish is somewhat more extreme.

After hundreds of years of selective breeding by the Chinese, goldfish have lost all of their physical characteristics. 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 crucian carp.

In just a few hundred years, the long, flat body that was suitable for fast swimming has now become a short, round body. The originally straight single tail has also evolved into a long and wide forked tail, and some caudal fins have become multi-lobed; some have protruding blisters; some have 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 in at that moment.

Different types of scalp tumors are essentially thin layers of epidermal cells.

As long as under careful human care, these deformed features will not affect the existence of goldfish. They just need to stay quietly underwater, in addition to eating or swimming, their genes can be preserved and passed from generation to generation.

Goldfish are raised to bring happiness to humans, and humans give them a “superior” life compared to wild species. However, many goldfish have too many physical variations, making them susceptible to sudden death. And people always crave new things, so hardly anyone can accurately predict what the future of goldfish will be like, what their upcoming changes will be.