CATDOLL : CATDOLL: How big a plastic tank is needed to keep Daphnia

1. How big a plastic water tank is needed to raise Daphnia

60 liters. Daphnia is a small crustacean, also known as fish worms. A 60-liter plastic box is needed to breed Daphnia. Daphnia refers to two major types of aquatic zooplankton, cladocerans and copepods. It is rich in nutrients and easy to digest. It is a palatable bait for fish fry and fingerlings.

2. How to raise high-fin black Mary?

The water temperature should not be too high, controlled between 80-100 degrees Celsius. The feed can be soy sauce, pepper, vinegar, scallion juice, cooking wine. In this way, your fish will enjoy the happiness in warm water.

3. Can Daphnia be frozen like bloodworms?

Reply to the original poster: If you have the conditions, you can raise Daphnia. If I remember correctly, the life cycle of Daphnia is only about 2 weeks. They mature quickly and reproduce quickly. If you raise them successfully, you don't have to worry about fish food. You can google Daphnia breeding. Among them, a Taiwanese fish friend has great breeding experience. At most, he had nearly a million Daphnia.

4. How to separate live and dead Daphnia

If you keep Daphnia in a basin of water, the ones swimming on the surface are alive, while the dead ones sink to the bottom.

5. Yellow eel breeding

The breeding of eels has become a relatively large industry in China. According to relevant data, there are more than 20 counties and cities in China with an annual output value of more than 100 million yuan for breeding eels. Without relatively lucrative profits, it is impossible for so many people to breed them. According to convention, if 20,000 yuan is invested in breeding eels, 30-40 cages can be raised, and the annual profit is generally about 20,000 yuan. Breeding eels has high economic benefits, but it is also a high-risk project, and its main risk is technical risk. If no one in the local area has yet to breed eels well, in order to reduce the risk, it is recommended to find a more reliable place to systematically learn the technical experience of breeding eels before starting. Eels are fish of the genus Eel of the family Synbranchidae in the order Synbranchidae, also known as eels, snakes, snake fish, and blood eels. Eels live at the bottom of water bodies and like to live in caves. They often dig holes in the bottom of water or embankments such as lakes, rivers, ponds, ditches and rice fields. The length of the eel's hole is about 3 times the length of the body, and the holes are curved and cross. There are usually more than two holes along each hole. The exit of the cave is often close to the water surface so that it can stick its head out to breathe air. The activity habit of the eel is to hide during the day and come out at night, that is, to stay in the cave during the day and go out of the cave to look for food at night. It can be caught at night based on this habit. The gills of the eel are in a degenerate state, and it mainly relies on the epidermis and auxiliary respiratory organs to breathe oxygen directly from the air. Therefore, it can live normally in water with very low oxygen content. Based on this, the density of artificial breeding can be increased. The surface of the eel is rich in mucus, and as long as the surface of the body is kept moist, it will not die, so it is very convenient to transport. The diet of the eel is mainly benthic animal food, such as water earthworms, snails, clams, tadpoles, small fish and shrimps, etc. In addition, it also eats some rotten debris, algae, melons and vegetables, etc. There are many special features in the breeding habits of the eel. The reproductive glands of female eels are different in size, the right side is well developed, and the left side is degenerate. Generally, fish can reach sexual maturity at the age of 2. The biggest feature of the eel's reproduction is the "sex reversal" phenomenon. From the embryonic period to the first sexual maturity, it is a female individual. After spawning, the ovary gradually turns into a testis. During the second sexual maturity, sperm is discharged, and then it is a male for life. If the eel is divided by its length, those with a body length of less than 22 cm are all female; around 36 cm, the number of males and females is half and half; individuals over 53 cm are all male. The spawning period of the eel is from April to August, and the number of eggs is relatively small, generally about 500. When spawning, the parent fish often spits foam at the entrance of the cave where they live, and the eggs are laid at the roots of aquatic plants or between the cracks of rocks near the entrance. The foam has the function of keeping the eggs. The fertilized eggs usually hatch into young fish in about 8 days. About 12 days after hatching, the young fish can actively swim and forage. During this period, the young fish rely on the protection of the male and female parent fish and the nutrition of the yolk sac. The growth of yellow eel is relatively slow. One-year-old fish can grow to 20 cm, two-year-old fish can grow to 30 cm, and three-year-old fish can grow to 40 cm. The growth rate of artificially cultivated yellow eel is related to whether there is enough bait. When there is enough bait, it generally grows faster than in nature. The activity of yellow eel is closely related to water temperature. The suitable water temperature for its growth is 15-30℃. When the water temperature is lower than 10℃, it stops eating and enters hibernation; when the water temperature is above 15℃, it starts to hunt normally; when the water temperature exceeds 30℃, it drills into a cave to spend the summer. 1. Still water pool breeding method Still water pool breeding is characterized by small water exchange volume, mud at the bottom of the pool for yellow eel to dig holes or artificial objects for yellow eel to live. The location of the breeding pool should be leeward and sunny, with a good water source, and the shape can be rectangular or oval, and the size depends on the breeding scale. There are two types of pool structures: cement pool and earth pool. Cement pools are usually of three types: above-ground, underground, and semi-underground. The water temperature of above-ground cement pools varies greatly with the seasons, which is not conducive to eel farming. Underground and semi-underground types are more commonly used. For the construction of earthen pools, choose a location with hard soil. It is best to lay a layer of felt on the bottom and wall of the pool, and the corners should be laid tightly. Then lay 20 cm (pool wall) and 10 cm (pool bottom) of soil on the felt. This can prevent water leakage and prevent eels from digging holes and escaping. Whether it is a cement pool or an earthen pool, it must be equipped with good inlet and outlet facilities. The diameter of the inlet and outlet pipes is 4 to 10 cm, and plastic nets or wire mesh are installed at the ports of the pool to prevent escape. After the eel pool is built, it is necessary to fill water to clean the pool. There are two purposes: one is to see if it leaks; the other is to use water to absorb and remove harmful substances in cement and mortar. Fill and drain the new pool 3 to 5 times, soaking for 2 to 3 days each time, which can basically remove harmful substances. After 10 days, 20 to 30 cm thick fertile mud is laid on the bottom of the drained pond. The fertile mud is made by mixing grass, manure and soil and then fermenting. After the fertile mud on the bottom of the pond is laid, aquatic plants such as water lilies, water peanuts, water hyacinths, etc. are planted in the pond to cool the eel pond and hide and inhabit for the eels. The water depth of the eel pond should be kept at 10 cm, and should not exceed 20 cm at most. Seven days before the eel fry is released, the fish pond should be cleaned and disinfected. 0.2 kg of quicklime per square meter of water surface should be evenly sprinkled throughout the pond. After disinfection, fill the entire pond with clean water. When releasing the eel fry, the water temperature in the eel fry transport container should not differ too much from the water temperature in the fish pond (3 to 5°C). The stocking density of eels is determined by factors such as the size of the eel fry, feeding and management conditions, and the amount of feed sources. Generally, when raising eels in small fish ponds, it is better to stock 2 to 5 kilograms of eel fry per square meter. If the scale of stocking is large, the number can be reduced accordingly, and if the scale of stocking is small, the number can be increased accordingly. If there is enough feed, more can be put in, and if there is insufficient feed, less can be put in. Because eels have the habit of eating small ones and killing each other, they should be stocked in ponds of different sizes when stocking. Be sure to choose eel fry with strong physique, no injuries or diseases, and neat specifications for stocking, and avoid mixing large and small eels. The best stocking scale is that each eel fry weighs about 20 grams. Too small or too large is not good. When raising eels at high density in fish ponds, it is the same as when transporting them. When stocking eel fry, some loaches should also be properly stocked. When loaches move up and down, the dissolved oxygen in the water can be increased, and the eels can be prevented from entangled with each other. Eels at different growth stages should be fed different feeds to ensure their nutritional needs. For the young eels that have just hatched for 4 to 5 days, they are mainly fed with water fleas, cooked egg yolks, soy milk, etc. Among them, live water fleas and live rotifers cultured in water are the best. Therefore, the water quality should be fertilized at this time so that there are sufficient water fleas and rotifers in the fish pond for the eel fry to eat. If the stocking density of eel fry is large, they can also be cultivated in another pond or scooped up from natural waters for the eel fry to eat. Later, as the eels grow up, they can be gradually fed with earthworms, snails and clams. At the same time, they should be matched with some plant feeds, such as wheat bran, rice, fruits, vegetables, etc. Among the feeds, earthworms have the best feeding effect, and every 5 to 6 grams of fresh earthworms can increase 1 gram of eel meat. In addition to collecting earthworms in the wild, earthworms can also be raised and bred in garbage and feces in front of and behind houses to supply the eels. Four rules should be adhered to when feeding. When the eel grows in nature, it has the habit of hiding during the day and coming out at night to forage. When it is first raised, it can be fed in the evening every day, and then the feeding time can be gradually advanced. After about 10 days of domestication, it can be fed three times a day at 9 am, 2 pm and 6 pm to ensure that the eel has sufficient bait. Each feeding should be flexibly controlled according to the weather, water temperature and the amount of residual bait. Generally, 5% of the total weight of the eel is fed. 2. Flowing water eel farming Compared with conventional earth pond eel farming, flowing water eel farming has the advantages of less land occupation, high stocking density, fast growth, high yield, convenient management and catching. Especially in places with geothermal water and factory waste water, using warm flowing water to raise eels has better benefits. Soilless flowing water fish ponds are best built indoors and made of cement bricks. The area of ​​the pool is generally 2 to 5 square meters, and the pool wall is about 50 cm high. Several pools can be connected in series. Each pool is equipped with inlet and outlet holes (two outlet holes, one above and one below), and the openings are blocked with mesh. A total water inlet channel and a drainage channel are set between each pair of pools. After the cement pool is built, close the total drainage hole, then fill it with water and soak it for more than 7 days to eliminate the floating dust of the cement. After the water is drained, fill it with clean water. Close the lower drainage hole and only open the upper drainage hole to keep the pool water at a certain depth and have micro-flow. If geothermal water or power plant cooling water is used, the water temperature must be artificially regulated according to the temperature at the time so that the yellow eel can grow well at a suitable temperature. In order to prevent the eel species from being infected with diseases, the eel species should be soaked in a 10 mg/L malachite green solution for 30 minutes before being released, and the eel species should be placed in the cement pool in time after disinfection. 4 to 5 kg can be placed per square meter. In order to make the eel species accustomed to artificial feeding, domestication can be carried out, that is, no feeding is given for 2 to 3 days after the eel species are released, so that the eel body becomes an empty stomach state. When hungry, eels have a higher feeding rate when fed artificial feed. Animal and plant feeds should be properly matched, and artificial compound granular feeds can also be fed. Due to the continuous supply of micro-flowing water, especially warm flowing water with geothermal water and residual hot water, eels can grow all year round, and the annual output per hectare can be as high as 150,000 kilograms or more. Although the investment in infrastructure such as cement pools in this breeding method is large, the economic benefits are very considerable due to the high output. Areas with conditions can adopt it according to local conditions. 3. Flowing water eel and earthworm co-breeding 1. Build a pond Choose a place with perennial flowing water to build a pond. The pond is a cement pond with an area of ​​30, 50, or 80 square meters. The pond wall is 80 to 100 cm high. The water inlet and outlet are set at the diagonal, and all are equipped with escape prevention equipment. 2. Pile up soil Pile up several soil ridges with a width of 1.5 and a thickness of 25 cm in the pond. The distance between the ridges is 20 cm, and the distance between the ridges and the pond wall is also 20 cm. The soil piled must contain loam rich in organic matter, so that earthworms can reproduce and eels can burrow and hide. 3. After the earthworm cultivation soil is piled up, keep the water depth in the pond at 5 to 10 cm, then put 2.5 to 3 kg of Taiping No. 2 earthworms per square meter of soil area, and spread 4 to 5 cm thick fermented cow dung on the surface of the ridge to allow earthworms to reproduce. Every 3 to 4 days, scrape off the upper layer of cow dung eaten by earthworms, and add 4 to 5 kg of new fermented cow dung per square meter. After about 14 days, earthworms will reproduce in large numbers and eels can be put in. 4. Stocking stocking density depends on the size of eels. Calculated based on the entire pond area, 4 kg per square meter for 30 to 40 per kilogram; 3 kg per square meter for 40 to 50 per kilogram. In this way, from April to November, the survival rate is above 90%, and the size is 6 to 10 per kilogram. 5. Management After the eels are put in, the water depth in the pond should be kept at about 10 cm, and the water should be kept flowing slightly. Scrape off a layer of cow dung on the surface of the bed every 3 to 4 days, and then add 4 to 5 kg of fermented new cow dung per square meter to ensure that the earthworms continue to reproduce and the eels feed on the soil themselves. No other feed is needed. This breeding method has good water quality and excellent live bait - earthworms for the eels to eat. Therefore, the eels are not easy to get sick, grow fast, have high yields, and have good economic benefits. Generally, 14 to 15 thousand eels can be produced per square meter.