Culture of Clarias fuscus

First, classification and distribution: Egyptian moustache catfish, also known as Egyptian pond lice, leather catfish, native to the African Nile river system. Trial culture was introduced into China in 1981 and autotrophic breeding was successful in Guangdong Freshwater breeding Farm in 1982. Now it has been promoted in most areas of South and Central China. It belongs to one of the high-yielding varieties of freshwater culture in Liangguang. Biology and ecology: Egyptian moustache catfish belongs to the family Claridae and Clarias. The body is cylindrical, the head is flatter than the local bearded catfish, the body is longer, the mouth is slightly lower, the tentacles are developed, and the eyes are smaller. There are many bone particles on the back of the head, arranged radially, the edge of the fin is reddish, there are black spots and gray cloud-like plaques on the side of the body, the chest and abdomen are white, and the mouth fissure is wide. The number of Gill rake, dorsal fin, thoracic fin, gluteal fin, ventral fin and vertebra were 52 / 90, 65 / 76, 8 / 9, 52 / 55, 1 / 5 and 58 / 62 respectively. The body length is 7 to 8.8 times of the body height, 4.6 to 5.2 times of the head length, 1.1 to 1.5 times of the body height and 2.8 to 3.2 times of the kiss length. 1. Life habits: Egyptian moustache catfish belongs to bottom fish and has a docile character. The environmental adaptability is strong, and the critical temperature of cold resistance is 7 ℃. Resistant to hypoxia, it can still survive when the dissolved oxygen is as low as 0.128ppm, and the lack of dissolved oxygen in the water often swims to the surface to swallow air. The intraspecific competition is fierce, and the law of the jungle and kill each other often occur in fish ponds and adult fish ponds. 2. Feeding habits: Egyptian catfish is an omnivorous fish mainly based on animal bait. Gluttonous, both plant feed and animal feed are preferred, and the growth rate is faster than that of animal feed. In natural waters, it mainly feeds on small fish, shrimp, aquatic insects, water earthworms, benthos and so on. In artificial culture, it can be fed to wild miscellaneous fish, silkworm pupa, fly maggots, clam meat, waste scraps from the slaughterhouse, etc., as well as artificial formula feed, such as wheat bran, flour, bean cake, etc., or the effect of extruded pellet feed made from these feed is better. 3. Reproductive habits: the age of sexual maturity of catfish is one year, and the smallest individual is about 100 grams. The breeding season is from April to October, the optimum breeding period is from early May to early July, and the optimum breeding water temperature is 2532 ℃. It can naturally spawn and reproduce in ponds, spawning habits like carp and laying sticky eggs. Parent fish have the phenomenon of nibbling eggs, so the hatchlings should be collected and hatched as soon as possible. The Egyptian moustache catfish spawned many times. The gonads of the postpartum parent fish matured again after intensive culture for about one month, and the gonads could be spawned 4 times and 5 times a year. Parent fish with a large number of eggs and weighing about 500 grams can lay about 10,000 eggs each time. 4. Growth rate: the growth rate of Egyptian moustache catfish is relatively fast, and the hatched seedlings of the same year can meet the commercial specifications. The average individual can reach 500 to 700 grams, and the largest individual can reach 1.5 to 2.5 kilograms. Pond main culture, in the case of adequate feed supply, the yield per mu can be as high as 15002500 kg, and the yield per mu can generally reach 7500100kg. Third, reproduction technology 1, parent fish cultivation: (1) parent fish pond: parent fish pond with an area of 1 mu and a water depth of 1.5 meters. The bottom of the pond is flat, easy to catch, good water source and convenient for drainage and irrigation. The parent fish should be cleaned and disinfected before entering the pond, and check the bottom of the pond and the bank for loopholes to prevent the fish from escaping. (2) stocking density: 150-250 kg of parent fish per mu (100-150 groups) is suitable. The stocking density of parent fish varies with water quality, and too high density affects gonadal development. (3) Feed and daily management: feed is mainly peanut cake and bean cake, supplemented by fish meal, silkworm pupa, fly maggots, fresh fish meat or waste animal scraps, etc. In the month before entering the growth period, animal bait should be given priority to to promote gonadal development. The feeding amount is fed at 10% to 15% of the body weight every day, divided into two times in the afternoon and in the afternoon. Fresh water should be injected once or twice a week for 2 hours each time. (4) parent fish overwintering: Egyptian moustache catfish has higher tolerance to low temperature than tilapia, and the water temperature drops to 10: 15 ℃ and begins to overwintering. The use of underground hot water, hot spring water, air-raid shelter, civil underground greenhouse or factory residual hot water can be used to survive the winter safely. 2. Sex characteristics and maturity of female and male fish: the surface mucus of female fish is abundant, the pigment is light, and the black spots on the side of the body are slightly less. The abdomen is plump, the external reproductive process is short round, the cloaca is long fissure, the reproductive process is far from the starting point of the anal fin, the color is light red. The body surface of male fish is rough, the body color is dark, and the side black spot is obvious. The abdomen is not plump and hard, the external reproductive process is long and strip, the cloaca is round and small, opening at the end, and the external reproductive process extends beyond the starting point of the anal fin. The abdomen of the mature female fish shows the outline of the existing ovary, with a sense of elasticity and softness by hand stroking, sometimes pressing out turquoise eggs, the reproductive foramen is tubular, the anus is slightly protruding, sometimes red and swollen. The male fish is straight, rarely swollen in the abdomen, the reproductive foramen is slender tubular, the end is pointed, reaching the base of the anal fin, and the anus is slightly concave and sometimes reddish. 3. Artificial breeding techniques: (1) the choice of inducing the birth of parent fish: the Egyptian moustache catfish can reach sexual maturity at the age of 1 winter and weighing about 100 grams, but the parent fish with a body weight of more than 250 grams should be selected for the first anniversary of breeding, physically strong, disease-free and injury-free. The eggs of mature female fish are of the same size and turquoise. If the egg is of different size or mushy, it is immature or overmature. (2) spawning pond conditions: the spawning pond is the most suitable square cement pond with a depth of about 50 cm, each pond contains 15-30 pairs of parent fish, the water quality of the spawning pond should be fresh, river water or purified tap water can be used, and the water depth can be maintained at 20-30 cm. Fish nests should be set up in spawning ponds. Fish nests are divided into sinking and floating. Floating fish nests can use the root whiskers of hyacinth, and the sinking can use palm, willow root or goldfish algae. The density of fish nests can basically cover the whole water surface, and there should be a certain number of fish nests at the bottom of the pond, which can reduce the sinking of fish eggs and adhere to the bottom of the pond. The fish nest should be washed and disinfected with 25% salt water before use. (3) the sex ratio, density and management of parent fish were slightly higher than that of male fish, and the suitable ratio of female to male was 1 ∶ 5. The spawning parent fish population should be 3-6 eggs per square meter of water surface. In order to prevent parent fish from jumping out during estrus and spawning, they can be covered with nets or bamboo mats. Keep quiet around the spawning pond, otherwise it will affect the spawning of parent fish. (4) the dose and effect time of induced labor: the artificial induced labor of Egyptian moustache catfish should be injected once, and the drugs should be induced by pituitary gland or chorionic gonadotropin of carp, and the effect of mixed use of the two is better. Generally, the dosage per kilogram of common carp pituitary gland is 2: 3, plus chorionic gonadotropin 500: 800 international unit, and the dose of male fish is 1: 3 of female. Using the pituitary gland of carp alone, there are 6 females and 1 males per kilogram. It takes 3-4 hours from induced spawning to oestrus chase and 10-16 hours to spawn. The effect time varies with the change of water temperature. (5) parent fish treatment for egg collection: it usually takes 3-4 hours from finding parent fish to stopping spawning. Therefore, 3-4 hours after spawning, the fertilized eggs together with the fish nest should be removed and hatched. At the same time, catch the parent fish to make it mature again. Be careful when catching parent fish so as not to damage the eggs in the pond. 4. Artificial hatching: hatching can be carried out in small mud ponds, net cages or shallow pools surrounded by plastic films, boards, etc. The eggs hatched in still water can hold 20,000 ~ 30,000 eggs per square meter, and the density of eggs hatched in running water can be increased. The key to hatching is to keep the water quality fresh and control the water level. According to the experiment of South China normal University, when hatched with purified tap water, the hatching rate is as high as 90%, with refreshing pool water, the hatching rate is about 80%, while with turbid well water or fertile water, the hatching rate is only 30% and 50%. The hatching water level should not exceed 0.5 meters, and it should be about 30 centimeters. In the process of hatching, direct sunlight should be avoided, and the temperature difference between day and night should not be too large. The cage should be cleaned frequently when hatching. The water temperature is 22: 25 ℃, the incubation time is 26: 36 hours, the water temperature is 25: 26 ℃, the water temperature is 22: 25 hours, the water temperature is 27: 30 ℃, the incubation time is 21: 22 hours. Fourth, fish fry cultivation: 1, cement pond breeding: cement pool is generally built into a square, the general area is 10 to 20 square meters, the pond height is about 1 meter. The stocking density of fish fry is about 3 cm, about 2000 fry per square meter. Under the condition of sufficient feed and about 15 days of cultivation, the specification of fish fry can be reached, and the survival rate of fish fry is higher. The technical points of cultivating fish fry in cement ponds are as follows: (1) strict control of water quality and water level, frequent replacement of fresh water, fresh water quality and a water depth of no more than 30 cm. (2) reasonable feeding. Fish fry are fed 2 days after hatching. In the first few days of feeding, water fleas and duck egg yolks filtered (50 mesh standard) can be used and fed 2 to 3 times a day. The daily dose of 10,000 fish fry is sprinkled with duck egg yolk along the edge of the pond. After 5 days, you can use water earthworms or fish meal (60%), flour (30%) and pupa powder (10%) to form a mixed feed. The amount of each feeding can be eaten within 5 hours, twice a day. (3) divide the pond in time to prevent the increase of density and anoxic floating head of fish fry. (4) prevent direct sunlight exposure. 2. Cage seedling raising: the size of the cage should be 10 square meters and 20 square meters. Net visual fish fry size matching. The cage is set in a pool with fresh water. The stocking density is about 10,000 tails per square meter. The feed supply is the same as that of raising seedlings in cement pond. Daily management should often clean the cage to prevent mesh blockage and ensure smooth water flow. 3. Raising seedlings in a plastic film pond: a rectangular wooden frame is formed on the ground with a wooden board, which is covered with a layer of plastic film, with a depth of 15cm to 20cm, with purified tap water, 10-15000 seedlings per square meter. The method of feeding and management is the same as above. 4. Pond flowering cultivation: Egyptian moustache catfish fry are cultivated in pond, which is basically similar to Sijie fish. The food source mainly depends on artificial culture of zooplankton and artificial bait. The area of flowering pond is about 0.3 to 0.5 mu, which requires that the water quality is fat and fresh, and the bait is rich in organisms. The flowering density is 100000 ~ 150000 per mu. Other management methods are the same as cement pool cultivation. 5. Adult fish culture techniques 1. Mixed culture in large ponds: this is a relatively common way of culture. That is to say, the species, specification and density of the original domestic fish species remain unchanged in the ordinary pond. After a few months of planting the domestic fish (that is, from July to August each year), 200,500 Egyptian moustache catfish (3cm) are placed in each mu of pond. The breeding method is fed and managed according to the common feeding method. 2. Monoculture: rural family fish culture can use small water bodies for high-yield culture, and monoculture can be used. It can be raised twice a year, the first time is planting in May, harvesting in August, the second time is planting in August and harvesting in December. The area of the monoculture pond is regardless of size, and 50 fish fry of 3 centimeters and 5 centimeters can be put into each square meter of water. The feed can use dead fish, earthworms, dried silkworm pupa, animal viscera, sour leftover rice, or peanut bran, or freshwater fish meal 60% + flour 20% + rice bran 15% + pupa meal 5% (fish meal can be replaced by meat paste of animal feed). The bait of early juvenile fish should be fine, which can be mixed with 80% fish meal and 20% flour. In the later stage, it is mainly coarse, which can be matched with a certain amount of livestock manure to reduce the production cost. Feed 1-2 times a day, accounting for 5%-10% of the fish weight. The amount of feed should be increased or decreased depending on the weather, water quality, and fish intake, so that it can be eaten within a few hours at a time.