The body is elongated, subcylindrical, head pointed long. Kiss sharp, beak-like. Mouth large, end position, lower jaw front center has a hard protrusion and upper jaw depression embedded. Whiskers absent, eyes small, slightly prominent. Hypopharyngeal teeth in 3 rows, teeth ending in hooks. Scales fine. Dorsal fin small, its beginning located after the ventral fin; caudal fin y forked. Body dorsum gray-brown, abdomen silvery white, dorsal and caudal fins dark gray, cheeks and other fins yellowish.
Lives in the middle and upper layers of rivers and lakes. It is a typical predatory fish with strong swimming ability, ferocious nature and quick action, often attacking and pursuing other fish, and once pursued, it is difficult to escape. Sexual maturity is 3-4 years old, the parent fish in April-June in the river rapids spawning. Young fish from the river swim into the subsidiary lakes to feed, fertilization, after the end of autumn, young fish and adult fish to the dry riverbed deep wintering. Growth is very rapid, after sexual maturity, the body length continues to increase, the largest individual up to 2 meters long, weighing up to 60 kilograms.
Widely distributed, from the north to the south of China's plains in various waterways are produced this fish. Rapid growth, 2-year-old fish weight 3.5 kilograms. Natural production is high, for the rivers and lakes in one of the large economic fish. However, it is regarded as the first "harmful fish" in the aquaculture industry because it devours a lot of other economic fish. Its meat is delicious, and has always been included in the large-scale superior edible fish. Each 100 grams of edible part containing 18.1-20.8 grams of protein, 1.3-5.4 grams of fat, calories 84-132 kcal, calcium 11-24 mg, phosphorus 144-203 mg, iron 0.7 mg, thiamin 0.04 mg, riboflavin 0.15 mg, 1.7 mg of niacin. Its meat is used freshly in medicine, has the effect of warming the middle, benefiting the stomach, stopping vomiting, the main treatment for weak spleen and stomach, regurgitation and vomiting, etc., should be taken regularly.
The Gan fish (Elopichthys bambusa Richardson), belongs to the carp family, Yarrow fish subfamily, also known as horizontal catfish, horizontal fish. Lives in the rivers and lakes in the middle and upper layers, swimming quickly, agile action, is a kind of mainly fish for food typical fierce fish, is also a large freshwater economic fish. The fish grows fast, large individuals, meat flavor, has always been regarded as high-grade freshwater fish. In recent years, due to the construction of water conservancy projects in mountainous areas, the deterioration of the water environment and other reasons, so that the Gan fish natural resources decline sharply, at present, in addition to the Yangtze River and the Yangtze River directly connected to the lakes can still catch Gan fish, the vast majority of rivers and lakes has been difficult to find Gan fish traces. 2003, we have Gan fish pond culture test, and successfully will be about 3cm summer flower fish species that year into an average of 600g / tail, up to 1.0g / tail. 600g / tail, the largest up to 1.5kg / tail specifications of commercial fish, survival rate of more than 90%. Now the relevant technology is summarized as follows.
1 Pond requirements
Pond area of 2 to 10 acres can be, the depth of water in 1.5 ~ 2m, solid pond ridge does not leakage, drainage and irrigation is convenient, the bottom of the pond silt thickness of not more than 20 cm.
2 stocking mode and density
2.1 Pond specialization
To Gan fish farming, in order to regulate water quality, each mu can raise a small amount of silver and bighead carp. Stocking density depends on pond conditions, management level. Generally per mu can be stocked about 3 cm Gan summer flower fish species 800, 50g / tail of bighead and silver carp and bighead carp age species 50 or so.
2.2 Fish and crab mixed culture
In the pontic fish pond, appropriate by raising river crabs, some Gan fish not eaten, sink to the bottom of the feed (fish) by river crab intake, let it act as a "scavenger", so that can reduce the water quality deterioration due to the residual feed decay, but also increase the benefits of breeding. Generally per mu can be stocked about 3 cm Gan fish summer flower fish 600 ~ 800 tail, bighead carp, bighead carp stocking number and "specialized" the same, per mu and then put the specification of 120 ~ 200 / kg of an age of crab species 100 ~ 150 or so. At the same time, in the pond water surface appropriate stocking water peanuts, pond bottom planting water plants (bitter grass or black algae).
3 Feed and feeding methods
Gan fish is fierce fish, in natural waters to live fish for food. But in artificial culture, if still feeding live bait, one is the breeding cost is higher, the second is to be equipped with feed fish special pool, and to do feed fish palatability, more trouble. Tests show that Gan fish by domestication, its food can by specializing in eating live fish and change to eat dead fish (fish). Therefore, Gan fish feed, pre available live fish fry, late for fish. Gan food domestication can be started from the fish length of 5 cm or so. Before the body length of 5 centimeters, should be fed live fish fry.
3.1 The preparation of live feed
Gan fish live bait can be used "four big fish" fry. Live bait preparation and feeding there are two methods. One is in the Gan fish breeding pond directly cultivation. In Gan fish in the pond half a month before, in each mu pond stocking fish splash 15 ~ 200,000, according to the summer flower fish breeding requirements for cultivation. When the fish fry grows to 1.5 centimeters, about 3 centimeters Gan fish species directly into the pond, to feed on the fish fry. Pond should continue to feed powder feed, cultivate feed fish, so that feed fish and Gan fish "synchronization" growth, to ensure that Gan fish at any time have the right bait. To Gan fish grow to 5 cm or so, and the pond in the live bait has been unable to meet the demand, began to carry on the domestication of the food, feeding the fish pieces of the mouth; Second is to cultivate live feed with special pond. In the breeding pond with mesh surrounded by a piece of pond total area of about 10% of the transient area, into the 3 cm Gan fish species, first feeding live fish fry, and then feeding fish fry and fish mixed material, and finally completely feeding fish, complete the transformation of food, remove the net. Compared with the two methods, the former is more convenient in the early stage of breeding, but domestication is relatively difficult, and the latter is the opposite.
3.2 Domestication
Select the pond with less silt at the bottom and facing south to the sun as the food ground, and carry out domestication twice a day, at 9:00 am and 4:00 pm. Domestication, first to the food court splash water, a few minutes after the start of the bait, and then repeat the splash water, bait, so the cycle, so that the fish form a conditioned reflex, as long as a food court splash water, that will quickly converge on the food court. At the beginning of the bait is best for the size of the live fish fry and small fish made of minced fish or fish pieces of the mixture, and then transition to all the fish pieces.
3.3 Feeding
The completion of the transformation of food, should be timed, fixed-point, quantitative feeding of fish pieces, generally on, afternoon each time, feeding before the first "splash water to attract fish", to be Gan Yu gathered in the food court, and then feed the fish pieces. Feeding according to the weather, water temperature and fish feeding situation, the general daily feeding for the fish body weight of 5% to 8%. Such as feeding frozen fish mainly, should be supplemented at certain intervals feeding fresh fish, or frozen fish with vitamin C and vitamin C.
4 daily management
4.1 Strengthening the water quality regulation
Guarantee that the daily management of fish farming and other fish farming is basically the same. In the breeding should pay attention to the control of water quality, keep the water fresh, rich in dissolved oxygen, transparency should be controlled in more than 30cm. The first stage is mainly water injection, which can be added every half a month, so that the pool water deepens as the fish body grows. In the middle and late stages of the water should be changed at the right time, and regularly sprinkle lime to the pool, can also be applied to the compound biological agents to improve water quality. In hot weather, we should increase oxygen at the right time to prevent anoxia floating head.
4.2 Timely sub-nutrient
Fish rush fierce, large food, fast growth, but individual differences are great. Therefore, breeding, such as not timely screening sub-nutrients, will result in large fish grabbing food, eat more, grow faster, small fish can not grab food and grow slower results. At the same time there will be "big fish block small fish can not eat into, small fish block big fish can not eat enough" phenomenon. Eventually caused by the same pond to raise the weight difference of more than 10 times the end. Therefore, in the breeding process should be based on the growth situation, timely sub-nutrition.
4.3 Disease prevention and control
The Gan fish pond culture has just begun, has not been found peculiar disease, but in the breeding process should pay attention to the prevention of disease. First, the breeding pond before the use of 75 ~ 100Kg per mu of quicklime sprinkled, in order to improve the pond substrate and kill germs. Secondly, the fish species should be sterilized by soaking in salt water before going into the pond. Third, the feed fish should be safe and hygienic, meet the relevant requirements, and regularly disinfect the food court with bleach or strong chlorine essence.
5 Discussion
The Gan pond culture can be successful, the key is to eat live bait by eating its food domestication into eating fish or dead fish. Domestication time, namely Gan fish in the growth to how big specifications when the start of domestication, on the success or failure of domestication and culture survival rate has a greater impact. This test will use live bait Gan fish feed to 5 cm after domestication, we think is more appropriate, because the natural waters of Gan fish to live fish for food, make its change to eat fish or dead fish, there must be a "forcing" process, Gan fish only hungry to a certain degree before forced to change to eat fish. Early domestication, may Gan fish individual smaller, weaker and affect the survival rate. Domestication is too late, and to the preparation of a large number of live feed fish bring difficulties. The test also shows that, in Gan fish 5 cm or so began to domesticate, generally a week time can complete the food transformation, and the survival rate can reach more than 90%.
On the feeding of feed. This test through the Gan fish food domestication, with fish as feed will Gan fish raised into commercial specifications. In the future, the pellet feed farming Gan fish technology research. (Mi Guoqiang Lu Binhui)
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