Biological characteristics of goldfish
1 Body color
Crucian carp in nature is basically silvery gray, which is caused by the black gray pigment and reddish yellow pigment in the skin, and the slightly blue reflective quality. Due to the change in the number, distribution, number and other conditions of pigment cells, the color of the goldfish body has also changed, resulting in many colors such as red, yellow, white, black, purple, blue and five flowers.
The color of wild crucian carp is dull and not distinct, while domestic goldfish have many bright colors. On the surface, it seems that goldfish produce many new pigments in the process of domestication, but in fact, the pigments present in the goldfish's body are also present in wild crucian carp. There are only three color components of goldfish: black pigment cells, orange pigment cells and light blue reflective tissue, all of which are found in wild crucian carp, because the recombination of these three components brings about changes in strength and density, resulting in a bright and varied body color of domestic goldfish. In recent years, with the progress of fish physiology research, there has been a further scientific explanation for the causes of body color changes in fish. In general, the change in body color of fish is caused by many reasons, such as the nutritional composition of fish food, the content of trace elements in natural waters, the depth of water, transparency and the color of surrounding objects and other environmental conditions can cause changes in the proportion of various pigments and related substances in the scales of the fish body, so that fish in different waters have differences in body color. For example, fish living in waters with less transparency and lighter waters are generally lighter in body color, silvery gray or light brown; fish living in waters with greater transparency are generally darker in body color, and some are darker. This is a physiological color change, and fish will react to the color of their surroundings by changing their color to adapt to the environment.
During the growth process of goldfish, there will be a fading phenomenon, and the color of black goldfish such as ink dragon eyes, ink bubbles and other varieties will change with age. Some black goldfish species will fade to orange-red or red-black within 2-3 years, and some fade into black and white, and the color remains unchanged for those who are fine. All species of goldfish are gray-brown in the juvenile stage, and after a certain period of time, they will develop into the body color of adult fish, and purple, transparent scales and multicolored goldfish can be distinguished earlier in the juvenile stage.
2 Body shape
Wild crucian carp have an oblong oval shape and flattened sides, while goldfish have a short, rounded body shape and a bulging abdomen. At the same time, goldfish are divided into two types: long body and short body, such as the chinese goldfish are mostly long body type, and the egg species goldfish is short body type. According to scientific measurements, the goldfish body height and head length ratio is the same as that of crucian carp, due to the shortening of the goldfish body length, so that the goldfish body height seems to be higher than the crucian carp. The author personally believes that changing the body shape of a wild crucian carp to the shape of a colorful goldfish is simpler than changing the body color. The main reason for the change in its body shape is to artificially change the external environmental conditions.
3 Fins
The dorsal fin of goldfish is divided into two types: dorsal fin and no dorsal fin, all wild crucian carp and most goldfish have dorsal fin, and a few species of dorsal fin disappear and the back is smooth. Egg species goldfish are all dorsal finless goldfish, and other dragon-backed species are also dorsal finless goldfish. As far as the fin is concerned, the fin of all wild crucian carp is a single fin, while goldfish generally use the double fin as the upper product, and the single fin is mostly eliminated at the juvenile stage.
The difference in the caudal fin is one of the fundamental factors that distinguish crucian carp from goldfish, crucian carp are single-tailed fins, while in goldfish, except for grassed goldfish, other species are bi-tailed fins, three-leaf tails or four-leaf tails. In terms of specific distinctions, there are many variations such as long tail, short tail, wide tail, phoenix tail, butterfly tail and so on.
In addition, the fins of goldfish also have corresponding variations in color, resulting in precious goldfish species such as panda butterfly tail and twelve reds.
4 Head shape
There are a large number of head shape mutants in Chinese goldfish, which can be divided into tiger head, lion head, high head, shouxing head, goose head and so on according to their specific forms. Not only that, even goldfish with the same head shape will be called differently in different places, such as tiger heads raised in the north, called lion heads in the south; those called hats in Beijing, and high heads in the south. Therefore, the naming of the head shape will vary from region to region. According to Professor Chen Zhen's analysis of goldfish variation, the head shape is divided into three types: flat head, goose head and lion head, in addition to these three types, there are two other types, namely: tiger head type and crown type. The head sarcoma of the tiger head goldfish is different from the lion's head, so it is listed separately, and the head shape of the crown pearl is more special and will also be described.
Flat head type: the skin of the head is thin and smooth, without sarcoma bulges, and there are wide and narrow parts.
Goose head type: there are vegetations on the top of the head, called sarcoma, and the sarcoma on the gills on both sides is underdeveloped, which is the main feature that distinguishes the lion-headed goldfish. This type of goldfish sarcoma develops well at the top, and after improvement, it has derived valuable varieties such as red top white high head (crane top red) and goose head red.
Lion head type: goldfish with dorsal fins, the top of the head, cheeks and gill lid are full of sarcoma, the gill cap is particularly developed, even can wrap the eyes. The sarcoma on the top of the head is thick and raised, and the front looks square and strawberry-shaped. The sarcoma can wrap the cheeks downwards, like a lion with its head held high.
Tiger head type: goldfish without dorsal fins, with a developed sarcoma at the top of the head, extending downward below the eyes and even to the gill cap. The main difference between the tiger head type and the lion head type is that the tiger head type belongs to the egg species goldfish, while the lion head type belongs to the cultural goldfish.
Crown type: The head shape of the crown pearl is extremely aesthetic, giving people the enjoyment of beauty, while the disease resistance is super strong, rarely affected by bacteria, and is the most resistant variety among all the varieties with sarcoma on the head. Some are egg-shaped, and some are divided in half, with fullness and roundness as beauty.
5 Eyes
Goldfish eye types can be divided into normal eyes, longan eyes, skyward eyes and blister eyes, and their eye areas are significantly different from normal fish after eye mutation.
Normal eyes: Like wild crucian carp, most goldfish species have normal eyes.
Dragon eye eye: the eyeball is bulging and expanding, protruding outwards out of the orbit, and there are different types such as apple eyes, abacus eyes, light bulb eyes, and grape eyes. Dragon's Eye and Butterfly Tail are representative species of Dragon's Eye Goldfish.
Skyward eye: Similar to the dragon's eye eye, the eyeball is protruding from the orbit, the difference is that the eyeball is flipped upwards at 90 degrees, looking at the sky, so it is called the sky eye or the eye of the sky. It mainly includes two varieties: egg species Chaotian Eye and Wen Species Chaotian Eye.
Blister eye: The eyeball is the size of a normal goldfish, and two translucent blisters grow under the eyelids, which are filled with tissue fluid and are wrapped in a thin film. There are microvascular vessels in this membrane that provide nutrients to the blisters. Blister eyes are divided into soft bubbles and hard bubbles, and the general blister eyes are soft bubbles. Another type of blister is small and hard, with a crescent-shaped bulge under the eye socket, looking down like a bulging frog, called a frog head or toad head.
6 Scales
Goldfish scales can be divided into three types: normal scales, transparent scales and pearl scales. The scales of the normal scales are the same as those of wild crucian carp.
Transparent scales: The scales are the same as normal scales, but there are no pigment cells or reflective tissue on the body surface, so they look as transparent as glass, and some can see red gills through the gill lid. This type of goldfish is often mistaken for having no scales, but in fact has transparent scales.
Pearl scales: This type of scale is different from normal scales, there is a large amount of calcium accumulated on the scales, and the central part is a hard hemispherical bump, like a grain of crystal full pearls, hence the name, mainly including wen pearls, crown pearls and other hybrid varieties.
7 Other parts
Gill caps: There are two kinds of normal gill caps and flipper gills. Flipped gill goldfish refers to the gill lid on both sides of the goldfish that is turned outward, the posterior edge is rolled outward, and the gill filament is partially exposed. Due to the flipping of the gill cover, the gill filament is exposed, which is easy to cause microbial invasion and produce lesions.
Nostril membrane: there are two kinds of normal membranes and pompoms. Most goldfish have a normal nasal septum, but there are also goldfish with abnormal development of the nasal septum, which grows 2 to 4 diaphragm folds, forming a spherical shape that extend outward into a bouquet of fleshy flowers attached to the top of the snout. The trait of growing diaphragm folds due to abnormal development of the nasal septum is called pompom, and when the goldfish swims, the pompom swings up and down with the body. The development of the nasal septum is symmetrical, isometric, and not loose, and the large can grow to 1/3 to 1/2 of the head.
Jaw: The jaw of the fish body mutates, growing one or a pair of blisters, called jaw bubbles. Unlike normal blisters, the eyes are filled with lymph, but open blisters that lead to the mouth. When the fish absorbs water, the jaw bubble will suddenly grow and small with the breath, so it is also named "play bubble". Jaw bubbles require left and right symmetry, the bubble body is large and small, small delicate, large plump, the largest diameter of about 35 mm.
The variation of each single trait of goldfish, or the different combinations and combinations of multiple traits, has formed many different varieties, which have developed to more than 300 varieties of eighteen major strains. The external morphology of goldfish has such significant and colorful variations, especially in various parts of the body that are so important to the life of the organism, such as the eyes, fins, gills, etc., which is probably rare in the animal kingdom. The variation of goldfish is produced by mutation and hybrid recombination. Its variation provides direct or indirect evidence for biological evolution.
