CATDOLL : CATDOLL: How many eels can be fed with one pound of fresh fly maggots? Can we feed them like this every day?

How many eels can be fed with one pound of fresh fly maggots? Can we feed them like this every day?

Don't feed only one kind of fish, the eel won't grow big

Enough for about ten kilograms of fish

How to disinfect eel farming? Including selection of species, water plants, water, daily disinfection, feed, maggots and earthworms

Eel meat is delicious and nutritious, and is said to be "better than ginseng". It also has high medicinal value. It is increasingly valued among aquaculture species, and its price remains high. The key points of aquaculture technology are introduced as follows:

1. Construction of eel pond

1. The cement pool area should be 30 to 50 square meters. The pool surface and bottom should be polished smooth to prevent eels from scratching their skin and causing infection with various bacteria and viruses. The top of the pool should be about 30 centimeters above the water level, and a natural overflow outlet should be set. The outlet should be fixed with a mesh to prevent the eels from escaping. There are two ways to raise eels in cement pools: with soil and without soil. Both methods require planting water peanuts or water hyacinths to regulate the water temperature and provide a rest area for eels in hot seasons. The entire pool can be planted with only a small portion of the feeding port. If it is soil breeding, it is advisable to lay 20 cm to 30 cm of soil, and the water level above the mud layer should be maintained at 20 cm to 25 cm. If the water is too deep, the eels will consume too much energy in the activities, and if it is too shallow, the water body will easily become turbid and the water temperature will change greatly. If it is soilless breeding, the water level should be maintained at 30 cm to 40 cm. The advantage of this breeding model lies in its good water disinfection effect, while in soil breeding, it is difficult for the disinfection drug to act on the soil and the bottom, and it is easy to breed various parasites and their intermediate hosts, such as leeches, flat leaf snails, and lymna snails.

2. Paddy field farming: First dig up the soil in the paddy field, bury the net cage, then put the soil back into the net cage, fix the four corners of the net cage, plant water peanuts or water hyacinths, and the area should be 20 square meters to 30 square meters. It is not suitable to plant crops with rough and developed root systems such as rice in the net cage, because eels have the habit of drilling soil and easily scratch the skin.

3. All kinds of ponds, lakes, and reservoirs are used for net culture, that is, soilless culture in cages. The area should be 15 to 20 square meters, which is convenient for disinfection and treatment. When the disease occurs, the cage and the fish can be directly placed in a large disinfection container. Aquatic plants such as water peanuts or water hyacinths should also be cultivated in the cage for the eels to rest.

The area of ​​the above-mentioned breeding models should not be too large. If it is too large, it will easily cause the size differences of eels to increase during the breeding process, which is not conducive to their growth.

2. Seed selection

You should choose the yellow eel species with large and dense black spots, as this type of eel grows the fastest; the yellow eel with small and irregular spots grows averagely; the yellow and black eel grows slower; and the jet-black or blue-black eel grows the slowest, but this type of eel is relatively ferocious.

When choosing seedlings, be careful not to choose those that are injured, electrocuted, hooked, or trapped. Instead, choose healthy, energetic seedlings that have strong ability to swim against the current and react quickly to a gentle touch on their tails. When choosing seedlings, choose seedlings of the same size, because eels cannibalize each other, which is very likely to happen when there is not enough bait.

3. The influence of water temperature and pH value on eels

Yellow eel is very sensitive to the change of water temperature. The suitable water temperature for its growth is 15℃～30℃. At 28℃, it is most active, grows fast and has high feed utilization rate. During this period, we should pay attention to feeding the eel with feed to make sure it is full. When the water temperature is below 15℃, yellow eel will not eat and will enter hibernation. Therefore, in the north of the Yangtze River, when the water temperature is unstable in April, do not add water to the pond or feed the eel to lure it out of the hole, so as to avoid the large change of water temperature causing eel disease. Eel can use wet method to overwinter, the method is: first drain the water and keep the soil layer wet. When it is cold and snowing, add a layer of straw or hay to keep warm and prevent ice. Deep water overwintering method can also be used, but there is a disadvantage. When the weather warms up in the second year, the eel's activity will increase and it will come out of the hole to look for food. However, due to the unstable weather and water temperature at this time, the eel is prone to colds and other diseases.

pH value is also called acidity and alkalinity. During the breeding process, if there is insufficient dissolved oxygen, the oxidation process is inhibited, and the bait residue, organic matter, excrement, etc. gradually accumulate and are not fully decomposed, organic acids will accumulate and the pH value will drop, affecting the growth of eels. Therefore, during the breeding process, attention should be paid to changing fresh and clean water. Because eels like clean water quality, attention should be paid to changing water frequently and measuring pH value. Eels are generally suitable for living in neutral or weakly acidic waters (pH value between 6.5 and 7.2). When changing water, attention should be paid to weather and water temperature. Each time the water is changed, 3 cm to 5 cm is appropriate. It is advisable to slowly put in fresh water first and then slowly discharge old water. The same treatment should be applied during the disease season. Changing water too quickly can easily cause a large temperature difference, which can cause eels to catch a cold.

4. Fish Pond Management

1. Disinfect the fish pond before stocking the fry. The disinfection time should be set about 10 days before stocking the fry. If it is too late, the fish pond may have residual poison, and if it is too early, it is easy to breed bacteria again. When disinfecting, keep the pond water 5 cm to 6 cm high and use 90 g/m2 to 120 g/m2 of quicklime for disinfection. The next day after disinfection, it is best to stir the mud and lime milk with a rake to make it fully play its role. When disinfecting, add new water every 1 to 2 days and drain the old water.

2. Disinfection and stocking of fish fry Before stocking, in order to determine whether there are residual poisons in the fish pond, 2 to 3 silver carp or bighead carp fry of 5 cm to 10 cm can be used as "test water fish" at the rate of 2 to 3 fry/m2. If the fish are active normally, the toxicity has disappeared. Otherwise, stocking should be postponed. Before stocking, the fish fry should be disinfected by immersing them in 3% to 5% salt for 10 to 15 minutes, or 2ppm to 5ppm potassium permanganate, which can eliminate some pathogens and parasites and increase disease resistance. It is best to disinfect in a cool place to avoid exposure to sunlight. The time can be appropriately increased or decreased according to the physique of the eel fry to see if the fry is abnormal. After disinfection, put them in clean water for temporary stocking in preparation for stocking. When stocking, they should be divided into ponds according to their size to avoid killing each other. It should also be noted that the water temperature of the temporary stocking pond should be equivalent to that of the large fish pond (i.e. the stocking pond). The temperature difference between the two should not exceed 3℃. If the difference is large, the water temperature should be adjusted appropriately.

3. Feeding, management and growth: Start adding some new water about a week after the eels are put into the pond, and then add water once every 2 to 3 days, with 3 to 5 cm of water added each time, so that the water level is maintained at around 25 cm. When it is hot in the summer, the number of water changes can be appropriately increased, with 3 to 5 cm of water added each time, to avoid excessive temperature differences.

Patrol the pond every day, and remove sick eels in time to analyze the cause of the disease (sick fish generally do not enter the hole, but float on the water surface). Adhere to intensive breeding, and feed them at regular times, fixed locations, and with fixed quality and quantity. For disease prevention, 1PPM bleaching powder or 0.2PPM trichlorfon can be sprayed throughout the pond (90% crystal form). Several varieties of disease prevention drugs should be prepared and replaced frequently to prevent pathogens from developing drug resistance.

The growth rate of eels is closely related to the nutritional content, type and quality of the bait. In traditional breeding, small fish, shrimps, earthworms, river clams, snails, etc. are used, but the freshness is difficult to guarantee, and they are easy to spoil and deteriorate, and eels are prone to disease. The nutrients are relatively simple, basically protein-based, and the protein content of these introduced wild fish is not high. The digestive organs of eels are weak, and they are not easy to spoil and deteriorate, and eels are prone to disease. The nutrients are relatively simple, basically protein-based, and the protein content of these wild fish is not high. The digestive organs of eels are weak, and they are not easy to digest and absorb, which is not suitable for the growth requirements of eels. In particular, fresh ice fish and clams are more difficult to digest and absorb, and are very likely to cause enteritis. Feeding earthworms is prone to various parasitic diseases. Because earthworms live in moist and fertile soil, and various parasites also like to reproduce and lay eggs in this environment, earthworms have become an indirect infection of eels. In order to improve economic benefits, larger eel fry should be selected to achieve the purpose of listing in the same year. Therefore, eels should be fed with complete and easily digestible and absorbable complete feed. There are three types of eel compound feed on the market, namely powder, granular and expanded feed. Powder and granular feed inevitably have the disadvantages of easy loss, water pollution, and difficulty in observing feeding conditions. Expanded feed has good floating properties, high stability in water, light water pollution, and easy observation of feeding conditions. In addition, expanded feed is sterilized at high temperature during the expansion process and does not carry pathogens. It is the first choice in breeding feed. Farmers should choose good feed manufacturers and well-known brands to ensure product quality. The "Yinxiang" and "Fuxing" brand eel expanded feeds on the market have been recognized by the majority of farmers.

V. Major diseases and their treatment

1. Bleeding disease

The cause of the disease is unknown, but it is of a septicemic nature. Eels fed with earthworms are more likely to develop this disease because parasitic diseases can easily lead to secondary hemorrhage and enteritis.

(1) Symptoms: There is bloody liquid in the mouth, which will flow out when the fish is turned upside down, and it is more obvious after death. The body surface is covered with bleeding spots of varying sizes, especially on the abdomen. The anus is red and swollen, and the fish is bleeding. The sick fish often floats to the surface to take a deep breath, which is called "vertical stake" by local farmers in Hubei. The fish keeps turning around in circles. When the belly is cut open, the liver is hemorrhagic and enlarged, the spleen is enlarged and purple, and the rectum is bleeding.

(2) Treatment A. Spray the whole pond with 0.2ppm-0.35ppm furazolidone (using original furazolidone powder). B. Take 5g of norfloxacin per 100kg of fish orally and mix with feed. C. Soak tobacco leaves at a depth of 30cm/mu in 250g warm water for 5-8 hours and spray the whole pond. D. Soak the diseased eels in 250,000 units of erythromycin. A and B above can be used at the same time, and A and C can be used alternately every other day for 3-5 consecutive days.

2. Red skin disease

(1) Symptoms: The diseased fish moves slowly and weakly, with their heads sticking out of the water all day long. They have local bleeding and inflammation, red plaques, mostly on the abdomen, severe epidermal rot, and intestinal congestion and inflammation. The difference from hemorrhagic disease is that the fish will not circle.

(2) Treatment A. Spray 1ppm bleach solution throughout the pond for 3 consecutive days. B. Soak the diseased eels in erythromycin.

3. Enteritis

It is mainly caused by feeding rotten and spoiled ice fish clams or due to insufficient feeding and excessive hunger.

(1) Symptoms: Slow movement, no food intake, dark blue body color, weight loss, intestinal congestion, yellow mucus discharge, red and swollen anus, and in severe cases, purple.

(2) Treatment: For prevention, use 5 kg of allicin or Polygonum hydropiper for every 100 kg of fish. Add 3 kg to 4 kg of mint to every 100 kg of eels and boil water and sprinkle once every 7 to 10 days.

For treatment, use per 100 kg of fish:

A. For humans, mix with 20 ml of Ten Drops water.

B. Mix 10 grams of sulfaguanidine with feed for 3 days.

C. Mix 5 grams of norfloxacin into feed for 3 to 5 days.

4. Most of the earthworms fed with capillaries and acanthocephalus will be infected. They are white and slender worms that can easily cause enteritis.

(1) Treatment:

A. Spray 0.5ppm~0.7ppm solution of 90% crystalline trichlorfon throughout the pond. Adequate water source should be prepared for spraying, because eels are very sensitive to trichlorfon, and improper dosage will cause death in the entire pond. Oral administration of trichlorfon is prohibited.

B. Take 5g to 7.5g of levamisole or the same amount of albendazole for every 50kg of eels every 6 days.

C. Spray a mixture of copper sulfate and ferrous sulfate (5:2) 0.7ppm throughout the pond to kill parasites.

5. Trypanosomiasis can easily cause anemia and enlarged head. Use the same medication as (4) and soak in the same amount.

6. Tail rot is mainly caused by insufficient bait, cannibalism or self-mutilation. Catch the fish and soak them in erythromycin or sprinkle them with 1ppm bleaching powder.

7. Coma is mainly caused by hot weather, high temperature and shallow water. You can add a certain amount of clean water and chop fresh clam meat and sprinkle it into the pond, or chop fresh gourd and sprinkle it in.

8. The water temperature is too high or too low, or a sudden large amount of water change may cause fish dysfunction and death. Maintain the water level and change the water reasonably.

9. Fever is mainly caused by high density, hot weather, excessive secretions of fish in the water, oxygen consumption, unclean water quality, bait residues or small fish and mussel meat that have not been eaten and not fished out, which makes them smell bad. The prevention and control methods are A. changing the water; B. spraying with 0.7ppm ketone sulfate or 300,000 units of penicillin in 25 kg of water.

Disinfection is a bactericidal drug. There are special disinfectants for eels. It can be used once every 15 to 20 days or once a month, depending on the water quality.