2. Goldfish is a kind of temperature-changing animal, which has strong adaptability to water temperature. Its body temperature changes with the water temperature, and it can survive at the water temperature of 0-39 degrees Celsius. But goldfish can't adapt to the drastic change of water temperature, and the sharp rise or fall of temperature over 5 degrees Celsius may endanger the life of goldfish. The optimum temperature for goldfish growth is 20-28 degrees Celsius. At this water temperature, goldfish grows most vigorously, with the largest food intake, excretion and oxygen consumption, and is the most lively goldfish.
3. Goldfish has a wide range of food habits and belongs to omnivorous fish with animal feed as its main food. Food is required to be rich in protein, fat, carbohydrates, vitamins, inorganic salts and trace elements. Goldfish eat bread crumbs, rice, leaves, shrimp, meat and so on. Goldfish prefer live food, and goldfish raised with live food grow better.
4. Goldfish has a strong adaptability to water quality, and has a certain ability to resist dirty water and acid and alkali. Water with pH value of 5.5 ~ 9.5 can survive. Alkaline water is more suitable for goldfish growth, but the alkalinity should not be too high and the pH value should not exceed 8.5. Goldfish will lose appetite, move slowly and grow stagnant under acidic water. Although goldfish can adapt to a wide range of water quality, it can't stand the rapid change of water quality, which may easily lead to illness and even life-threatening.
In actual feeding, in order to keep the fish tank clean and full of oxygen, it is necessary to change water frequently. In order not to change the water quality and temperature sharply, the water is changed by mixing water. Don't change all the water at once, lest the water quality and temperature of goldfish don't adapt. If you can filter out food residue and excrement, you can change one tenth of the water every day. If you can't filter out food residues and excreta, you should replace one-third of the water every day, and the temperature will deteriorate quickly with high water. You can appropriately increase the number of water changes and the amount of water change every day, but you need to pay attention to drying fresh water to ensure sufficient dissolved oxygen.
1. Goldfish (collectively referred to as ornamental fish improved from crucian carp)
1, goldfish and crucian carp belong to the same species in taxonomy. (crucian carp)
2. Goldfish originated in China, also known as "golden crucian carp", which is similar to carp (Cyprinus carpio) but has no mouth whiskers. It is an ornamental fish evolved from crucian carp. There are many varieties of goldfish, and the colors are red, orange, purple, blue, ink, silvery white, five flowers and so on. , divided into four strains: literary species, grass species, dragon species and egg species. 12 century, the genetic research of goldfish domestication began. After a long period of cultivation and continuous optimization of varieties, goldfish from all over the world are now directly or indirectly introduced from China.
3. In the history of human civilization, China goldfish has coexisted with human beings for more than ten centuries, and it is the earliest species in the history of ornamental fish in the world. Goldfish are easy to raise. It has a strange posture, colorful, generally golden yellow and beautiful appearance. Goldfish can beautify the environment and are very popular with people. It is an ornamental fish with China characteristics. Goldfish in China are mainly developed from crucian carp. However, color carp has attracted great attention since it was introduced to Japan.
4. With the efforts of generations of goldfish farmers, China goldfish still tells the world the beautiful legend between movement and stillness. There is also a folk saying about goldfish in our country: buying two goldfish at home during the New Year means a long life in the coming year.
Second, the morphological characteristics
1 variety
According to statistics, there are about 300 kinds of goldfish, and new varieties are still emerging, which are basically divided into five categories:
1, grass goldfish: It looks like a crucian carp, but its color is bright, such as "red crucian carp".
2. Warm goldfish: It looks like a seal script, hence its name. It is basically similar to the dragon species, but the eyeball is not prominent, such as "Pearl (cultivated in 1900)" and "gill-turning (cultivated in191kloc-0/year)".
3. groups. Longan goldfish: It is a typical variety of goldfish with protruding eyes and four leaves (double tails) on the tail fin, such as "Tianzhu (cultivated in 1592)".
4. Oval goldfish: fat and egg-shaped, hence the name. Its main features are no dorsal fin and unobtrusive eyeball, such as "Tiger Head" and "Blister Eye (cultivated in 1908)".
5. Its evolution process is: wild crucian carp advanced into golden crucian carp, then developed into literary species through grass goldfish and golden crucian carp, and then evolved into two close relatives, namely dragon species and egg species.
2 colors
1. The color of goldfish is produced by many colored skin cells in the dermis.
2. There are only three color components of goldfish: black pigment cells, orange pigment cells and light blue reflective tissue. All these ingredients exist in wild crucian carp. The bright and changeable body color of domestic goldfish is only caused by the recombination and distribution of these three components, the change of intensity and density, or the disappearance of one, two or three of them.
3. Some individuals of the same species have different colors. The color of the same individual in some fish changes with the background in a certain range.
This is the special adaptation of fish to the living environment. This change, with different species, the ability and speed of color change will be different.
There are many fish that can change color, and goldfish is one of them. The change of color is mainly controlled by the nervous system and endocrine system, and the perception of most colors mainly depends on the head nervous system. Mainly to adapt to the color of the environment, there are other factors. For example, after electro-optical irradiation, some colors and stripes will be displayed. When the fish is injured, sick or lack of oxygen in the water, and the water quality becomes worse, the body color of the fish will become dark and lose its luster.
reference data
Baidu encyclopedia:/item/%e9% 87% 91%e9% b1%BC/32862? Fr = Aladdin #5