CATDOLL : CATDOLL: Can other fish be raised in eel ponds?

1. Can other fish be raised in eel ponds?

That depends on what you want to harvest. When stocking turtles in ponds, there are examples of raising them together with some large domestic fish, but this is generally only to improve the quality of the turtles. If you raise them together with eels, it is basically certain that you will not harvest any eels.

2. What is the actual yield of loach farming in rice fields?

The yield of loach farming is about 3,000 kilograms per mu! We are a two-season rice field in the Central Plains!

3. What are the difficulties in farming crabs and shrimps?

1. Breeding conditions

1. Pond conditions. The pond is close to the water source, with sufficient water, fresh water quality, electricity and access, quiet surrounding environment, and no industrial, agricultural and domestic pollution. The pond bank is wide and solid, the bottom of the pond is flat, and the soil is alkaline sandy loam. The middle of the pond is set as a beach field (shallow water area), accounting for 60% of the total area of ​​the pond, with the field surface facing upward and the water depth of 60 to 80 cm. Crab breeding ditches (deep water area) are dug around the pond bank, with a width of 2 to 3 meters and a depth of 1 to 1.2 meters below the field surface.

2. Inlet and outlet system. According to the requirements of high inlet and low outlet, an independent inlet and outlet system should be built. The inlet should be located at the highest water level at one end of the pond, and the outlet should be located at the lowest point at the other end of the pond. The inlet and outlet should be covered with polyethylene mesh or stainless steel mesh to prevent river crabs from escaping and enemies from entering. Dividing the inlet and outlet is conducive to water level control, sewage discharge, keeping the pool water clean and refreshing, and reducing the occurrence of diseases.

3. Anti-escape facilities. River crabs have strong climbing and escaping abilities, so antioxidant plastic sheets should be used around the pond to form an anti-escape wall. The plastic sheet should be buried along the inner side of the pond bank, with the bottom 20 cm deep in the soil and compacted, and the upper part 40 to 50 cm above the pond bank. There should be no gaps between the sheets, and the outer side of the sheet should be supported and fixed with wooden or bamboo piles, with a pile spacing of 1.5 to 2 meters. After punching holes in the plastic sheet, it should be fixed to the pile with thin wire, and the four corners should be made into arc shapes.

4. Aeration facilities. Microporous aeration is equipped according to the standard of 0.15 kW/667 square meters. The air supply pipe is erected in the middle of the pond along the east-west direction and extended to both ends of the pond. The strip installation method is adopted. A microporous pipe 10 to 15 cm above the bottom of the pond is horizontally set at intervals of about 10 meters on both sides of the air supply pipe. One end of the microporous pipe is connected to the air supply pipe with a plastic pipe, and the other end extends to 1 meter away from the bank of the pond.

2. Preparation before stocking

1. Clean and disinfect the pond. In winter, drain the pond water, remove weeds around the pond and excess silt at the bottom of the pond, leaving 5 to 10 cm of silt. After freezing and sunbathing, use quicklime to clean the pond in a dry method. The amount is about 100 kg/667 square meters. The method is to add water to make a slurry and then sprinkle it all over the pond while it is hot to kill pathogens and harmful organisms such as wild fish. After cleaning the pond, continue to expose it to the sun until the bottom of the pond is dry and cracked to improve ventilation conditions and accelerate the oxidation of organic matter.

2. Planting aquatic plants. Plant composite aquatic plants in the crab pond. Planting method: First, cut the stems of Elodea and plant them in sections, with a row spacing of 5 meters x 6 meters, and plant them throughout the pond; then plant Hydrilla verticillata, Vallisneria and Yellow Grass in the middle of the Elodea, so that the coverage rate of aquatic plants accounts for about 50% of the total area of ​​the pond. Aquatic plants play a very important role in crab and shrimp farming. They are not only plant bait for river crabs and a place to hide from enemies, but also can purify water quality and increase dissolved oxygen.

3. Fertilizer application. 10 to 15 days before stocking the seedlings, apply fermented and disinfected poultry manure into the pond, preferably chicken manure, with an application rate of 100 to 200 kg per 667 square meters. Apply biological fertilizer 20 to 30 days later, and the amount of topdressing depends on the water quality. Fertilization and topdressing can not only increase the reproduction of plankton and provide natural biological bait for crabs and shrimps, but also promote the growth of aquatic plants and inhibit the occurrence of moss.

4. Release snails. Snails are released three times. The first release time is from March to April, with a release amount of 200-300 kg/667 square meters; the second time is in June, with a release amount of 100 kg/667 square meters; the third time is in August, with a release amount of 200 kg/667 square meters. Reasonable release of live snails can not only provide animal live bait for river crabs, but also play a role in purifying the bottom water quality.

5. Set up a "special zone" for breeding. Before stocking crabs, a 10-mesh polyethylene mesh fence is used in the crab breeding ditch (deep water area) to form a "special zone" for breeding, which occupies about 20% of the area of ​​the large pond and serves as a "base" for intensive breeding of crabs.

3. Seedlings stocking

1. Stocking of shrimp fry. Fresh shrimp fry are stocked in January, with a stocking specification of about 2,000 per kilogram and a density of 20 to 25 kilograms per 667 square meters.

2. Stocking of crab seeds. Choose to stock locally cultivated crab seeds from the Yangtze River system. The stocking specification is 100 to 120 crabs per kilogram, and the density is about 1,000 crabs per 667 square meters, at the end of February or the beginning of March. First, place the crab seeds in the "special zone" for intensive cultivation. The cultivation time depends on the growth of aquatic plants and the reproduction of snails. When the coverage rate of aquatic plants reaches 40% and the snails have reproduced to a certain number (usually in May), the fence can be removed and the crab seeds that have been intensively cultivated can be placed in the large pond for breeding.

3. Stocking of fish. In order to make full use of the upper space of the water body, increase aquaculture output and improve aquaculture efficiency, some silver carp and bighead carp can be stocked in the pond. The stocking specification is 150-250 grams per tail, and the density is about 50 tails per 667 square meters. The time is April. Silver carp and bighead carp are responsible for the function of "cleaners" of the water body, keeping the water in the aquaculture pond fresh and clean.

4. Seedling disinfection: Before entering the pond, the above-mentioned seedlings need to be disinfected by soaking in 2% to 3% salt water for 5 to 10 minutes to kill bacteria and parasites on the surface.

4. What is the best thing to raise in crab ponds?

You can raise crucian carp and silver carp in the crab pond.

5. What are the requirements for water for raising crabs?

1. High water stability and strong self-purification ability

It mainly depends on three aspects:

The first is algae. 75% of dissolved oxygen in water comes from beneficial algae. If you want good water quality, you must first cultivate excellent algae. In the process of river crab farming, try to cultivate the diversity of pond environment organisms, maintain a certain fertility of the water to maintain the algae, maintain the stability of the water, and thus reduce the stress response of river crabs.

The second is microorganisms. In water bodies with fewer algae or deeper water, the ability of microorganisms to decompose organic matter and degrade ammonia nitrogen, nitrite, and hydrogen sulfide is the basis for water stability.

The third is chemical substances, such as sufficient dissolved oxygen and high concentration of buffers (such as alkalinity), which are important factors for water stability and water purification.

2. Good water quality indicators

Such as higher dissolved oxygen (greater than 5 mg/L), appropriate hydrogen and nitrogen NH4+ maintenance (0.1-0.5 mg/L), toxic NH3 (less than 0.1 mg/L), nitrite (less than 0.05 mg/L), hydrogen sulfide (less than 0.1 mg/L), suitable pH (7.5-8.5), etc.

River crabs are cold-blooded animals and do not have the ability to regulate their body temperature. The body temperature of river crabs changes with the water temperature, and their normal body temperature is slightly higher than the surrounding temperature. Changes in water temperature will directly affect the growth and metamorphosis of river crabs. Within the suitable temperature range, when the temperature is high, river crabs eat vigorously, and grow and metamorphose quickly. For example, when the water temperature is around 21 degrees, the first-stage zoanthid larvae only need about 4 days to metamorphose, and when the water temperature is around 15 degrees, the metamorphosis is slow. When the water temperature is around 10 degrees, river crabs eat significantly, and when it is below 10 degrees, their feeding ability is weakened. River crabs can tolerate low temperatures. When the water temperature is between -1 and -2 degrees, egg-bearing crabs can successfully winter, and neither the crab eggs nor the parents will die. In winter, river crabs stop eating and hide in caves to spend the winter.

The mating, spawning and metamorphosis of river crabs all have certain temperature requirements. For example, the temperature for parent crabs to overwinter should be below 6.5 degrees, and the temperature for parent crabs to mate should be 8-15 degrees. During the breeding stage of brooding crabs, the water temperature should be controlled at around 11-16 degrees, and the metamorphosis of larvae requires 19-25 degrees.

Water temperature has a certain impact on the feeding, molting and growth of river crabs. When the water temperature is above 10 degrees, they start to feed, molt and grow at around 15 degrees, grow vigorously at 20-28 degrees, and the best growth temperature is 15-25 degrees. If it exceeds 28 degrees, the molting of river crabs will be inhibited.

6. What is the ratio of crab and grass carp breeding in a 40-mu fish pond?

What is the ratio of crab and grass carp for increasing fish in 40 acres?

A: 50% grass carp and 50% crabs. According to regulations, if 50% grass carp is raised in one acre of fish pond, 700 grass carps can be raised per acre, 28,000 grass carps can be raised in 40 acres, 1,000 crabs can be raised per acre, and 40,000 crabs can be raised in 40 acres. The advantage is that crabs can eat grass carp feces, and grass carp and crabs can coexist harmoniously. Please approve!

7. What should we pay attention to when raising crabs and eels together?

No, crabs are greedy and will eat eel fry and other fish fry. It is best not to raise lobsters with crabs, as they will compete for food and eat each other's young. Lobsters will have a great impact on the ecological system of the entire water area, and therefore affect the normal survival of other organisms in the water area. Therefore, if a pond is raised with lobsters, it will be difficult to raise other animals.

8. What issues should we pay attention to when raising warm water fish?

1. Water temperature conditions and adjustment methods: Tropical fish are stenothermic fish. They have strict requirements on water temperature and are particularly sensitive to changes in water temperature. They can adapt to a water temperature of 20-30 degrees. Exceeding the upper or lower limit of this range can be life-threatening for most tropical fish - if the water temperature drops below 20 degrees, tropical fish will get sick or die; although the water temperature reaches 20 degrees, if it is too low for a long time, it will also affect their appetite and growth; excessive temperature difference between day and night, such as exceeding 5 degrees, can also cause discomfort to them, which will lead to illness and death over time.

2. There are generally two methods to regulate the temperature of water used for fish farming: one is to directly increase the temperature of the aquarium water, and the other is to indirectly increase the water temperature by raising the indoor temperature.

3. Water hardness and adjustment methods: Most tropical fish require soft water and low hardness water to live and reproduce. Water hardness is mainly determined by the amount of calcium and magnesium salts contained in the water. 8 degrees is soft water, 8-14 degrees is low hardness water, and 20-30 degrees is hard water.

4. Generally, rainwater and snow water are soft water. There are many red soils in southern my country, and the water hardness in the rainforest rivers is low, mostly soft water. The north has less rainfall, higher salinity and alkali content in the soil, and higher water hardness. Tropical fish are not as demanding on water hardness as they are on water temperature, and can adapt to water with higher hardness. However, they require water with lower hardness or soft water when breeding. Tap water is a common water source for breeding tropical fish. The easiest way to judge its hardness is to boil the water and look at the scale in the kettle. More scale means hard water, and less scale means soft water.

5. Water pH and how to adjust it: Water pH refers to the concentration of hydrogen ions in water. The pH value of water can be measured using pH test paper or a meter. For usage, refer to the instructions.

9. What kind of fish is better to raise with duck-billed fish?

In the method of mixed breeding, we need to reasonably control the species, quantity and proportion of fish to be raised. Usually, duckbill fish are mixed with silver carp and herbivorous fish, and the ratio of mixed breeding is controlled at 1:1:8. In order to prevent excessive nutrients in the water body, the number of aquatic plants planted also needs to be controlled, otherwise it is easy to lead to breeding failure.

10. When raising big crabs and crayfish together, will the crabs eat the young shrimps?

Since crayfish will compete with river crabs for food, oxygen, and aquatic plants, and both have the habit of self-mutilation and mutual destruction, traditional farming has always regarded crayfish as pests in crab ponds, and raising crayfish in crab ponds is risky. However, from the perspective of farming practice, it is feasible to raise crayfish in crab ponds. ⑴ Plant good aquatic plants. Since river crabs and crayfish will eat some aquatic plants, it is necessary to ensure the planting amount of aquatic plants in the crab pond, and the coverage area of ​​aquatic plants should account for more than 50% of the entire pond area, so as to minimize the impact between river crabs and crayfish. It is best to put crayfish in the crab pond after the aquatic plants grow up. ⑵ Feed enough and feed reasonably. Letting river crabs and crayfish eat enough is an important measure to avoid river crabs and crayfish killing each other. Therefore, it is necessary to accurately grasp the number of river crabs and crayfish in the pond and feed enough. When feeding feed, you should also add enough fresh snails. The amount of fresh snails per mu should be more than 250 kg, generally 250-500 kg. When feeding feed, you should follow the principle of "fine at both ends and coarse in the middle". When feeding a large amount of feed, you should pay attention to regulating the water quality to avoid a large amount of feed causing water quality deterioration and causing shrimp and crab death. ⑶ In the early stage of crayfish stocking, you should pay attention to fertilizing the water quality, apply some base fertilizer in an appropriate amount, and cultivate small zooplankton for crayfish to eat.