What is a freshwater fish? What kind of food do you often eat? How much does it cost to breed? What is the reasonable density? Hatching management techniques of attached fish eggs

Fish are the oldest vertebrates. They inhabit almost all the aquatic environments on earth-freshwater lakes, rivers to saltwater oceans and oceans. Then what is a freshwater fish? What kind of food do you often eat? How much does it cost to breed? What is the reasonable density? What are the techniques for managing the hatching of fish eggs?

What is a freshwater fish?

1. In a broad sense, fish that can live in freshwater with a salinity of 3/1000 can be called freshwater fish. In a narrow sense, it refers to fish that only have "juvenile" or "adult" in some stages of their life history, or have to spend their whole life in freshwater. There are about 26000 species of fish and more than 8600 species of freshwater fish in the world. There are nearly 3, 000 species of fish in China, of which there are more than 1000 species of freshwater fish.

two。 There are more than 26000 known species of fish in the world, which is the largest group of vertebrates, accounting for about 48.1% of the total number of vertebrates. Most of them live in the ocean, and there are about 8600 species of freshwater fish. There are nearly 3, 000 species of fish in China, of which there are more than 1000 species of freshwater fish.

What kind of freshwater fish do you often eat?

1. Mandarin Fish

Also known as mandarin fish, seasonal flower fish, has always been regarded as "the best fish", its meat is plump, thick and tender, delicious and less bone spur. Every spring is the most fat and beautiful season for Mandarin Fish, so it is also known as "spring fresh". As a delicacy at the banquet, Mandarin Fish is deeply loved by people, and his cooking methods are mainly steaming, burning and frying. The most famous "Sweet and Sour Mandarin Fish" is well known.

two。 Carp

Also known as red-tailed fish, red-tailed fish, dragon door fish, etc., the body is spindle-shaped, the mouth is located in the front of the head, there are two pairs of moustache. The body color is bluish yellow and the lower lobe of the caudal fin is red. Both the dorsal and anal fins have hard spines, and the trailing edge of the last thorn is serrated. There are many kinds of carp, especially the Yellow River carp is one of the four famous fish in China, the taste is fresh, tender and delicious. It is usually cooked in braised, steamed or braised dishes.

3. Anchovy

Because of its herbivorous livelihood, it is also known as grass carp, grass carp, grass stick, grass green, thick fish. Wan fish has green and white colors, and the white one tastes better. Anhui fish has delicate meat, few bone spurs and rich nutrition, which is rich in unsaturated fatty acids and selenium, which often has the effect of anti-aging and beauty.

4. Crucian carp

Also known as Xitou, crucian carp crutch (Hubei), crucian carp melon seed (northeast), river crucian carp (Shanghai), month crucian carp (Guangdong). Crucian carp is rich in animal protein and unsaturated fatty acids. Eating regularly can not only help to keep fit, but also help to lower blood pressure and blood lipids and prolong life. Eating crucian carp can appetizer to strengthen the spleen, regulate camp Shengjin, not only supplement the nutritional protein that produces floating juice, and spleen health can make milk secretion, so eating crucian carp does have the effect of increasing milk secretion to parturients with less milk and poor lactation.

5. Silver carp

Also known as silver carp, jumping silver carp, silver carp fish and so on. The scale is silver-gray, the mouth is large, the eye is in the lower lateral position, the ventral ventral fin is fleshy, and the end of the pectoral fin extends to the base of the ventral fin. Silver carp meat fresh and tender, can be cooked into fried fish, smoked fish, braised fish and other dishes.

6. Bighead carp

Also known as fat head fish, silver carp and so on. The flesh of the whole body is obviously concentrated in the head, the body color is dark green, and there is no obvious pattern. Bighead carp is a kind of fish with high protein, low fat and low cholesterol, which has a protective effect on cardiovascular system. Bighead carp has a large head and delicious meat, which is suitable for making Fish Head en Casserole, hot pot or Steamed Fish Head with Diced Hot Red Peppers.

7. Catfish

Also known as beard silver carp, pond lice, raw fish. The whole body is scaleless, the body surface is mucous, the head is flat and the mouth is wide, and there are four beards in the upper and lower jaw. The best eating season for catfish is between mid-spring and mid-summer. Catfish contains more protein and fat, which has a better therapeutic effect on weakness and malnutrition. The main cooking methods of catfish are burning, stewing and boiling.

8. Black fish

Also known as wealth fish, raw fish, black stick, snakehead and so on. The black fish is cylindrical in shape, its tail is slightly flattened on its side, its head is pointed, its long face is flat, and its scales are quite like snakeheads. In Guangdong and Guangxi, black fish has always been regarded as a tonic. Sichuan water is mostly used in the north, while soup is mostly boiled in the south.

How much does it cost to raise freshwater fish?

Common freshwater fish, such as the four major domestic fish, the general stocking density, including bait machines, oxygen machines and so on, costs 50,000 to 60,000 yuan. If it is a famous special fish, it will cost 9-100000 yuan.

What is the reasonable density of freshwater fish culture?

The reasonable seedling density should be determined according to the culture mode, technical level, water exchange conditions and bait supply. The stocking density used in various places should be adapted to local conditions according to pond conditions. For farmers who adopt the 80:20 pond fish culture technique for the first time, the weight of the main fish culture per mu of water shall not exceed the following limits:

1. In ponds where oxygen enrichment is limited and cannot be flushed, the weight of fish is set at 167 kg.

two。 In ponds with unlimited aeration and limited flushing, the weight of fish is set at 267 kg.

3. In ponds where there are no restrictions on aeration and flushing, the weight of fish is set at 400 kg.

4. Together with 20% of the weight of fish, the total weight of fish produced in a, b and c ponds is 209 kg, 333 kg and 400 kg, respectively.

5. If the average size of the pond is 500 grams, the total number of fish released in a, b and c ponds is 418, 666 and 800 respectively. Among them, the main fish culture accounts for 80%, and the fish culture accounts for 20%.

Warm water fish culture, the general water temperature is 15-30 ℃, such as carp, grass carp, silver carp, bighead carp, crucian carp and blunt snout bream and so on; cold-water freshwater fish culture: generally suitable temperature is 10-20 ℃, such as rainbow trout, fine-scale fish; hot-water fish culture: general optimum temperature is 18-30 ℃, such as tilapia, freshwater white Pomfret, etc.

Attached: hatching management technology of fish eggs

1. Cleaning and disinfection of incubator containers. Wash the incubator before putting the eggs into the incubator, thoroughly disinfect them, and check them carefully to prevent leakage. Often wash the sieve silk net after putting the fish eggs, especially before the fry comes out of the film, so as to prevent the egg membrane from attaching to the sieve silk.

two。 The water temperature, water quality and embryonic development were detected regularly. Focus on the prevention of water mildew and enemy damage.

3. During ovalization, different water flow was given according to different stages of embryo development. From egg cleavage to fish fry coming out of the membrane, the flow rate is controlled to prevent the eggs and larvae from sinking and accumulating, and the flow rate is generally 7.5L / kg 12L / min; after the fry comes out of the membrane to before horizontal swimming, the flow can be appropriately increased, and then reduced to about 5L/min after horizontal swimming to avoid excessive water flow, so as to make the fry swim in the top water and consume physical strength.

4. Stop the water to dissolve the film. When about 5% of the eggs have hatched, the intake valve is about to close, stopping the flow of water in the incubator and sinking the eggs. Generally, about 95% of the fish fry hatch after 15min, then open the valve immediately and flush the fry.