Method for hatching fish fertilized eggs and rearing fish fries by using rice field

Abstract

The invention discloses a method for hatching fish fertilized eggs and rearing fish fries by using a rice field. The method comprises the steps of rice field transformation, fertilized egg hatching, fish fry rearing, bait casting, fertilization and fish fry catching. The water level of the shallow ditch is deepened to 30-40 cm, fish nests attached with the fertilized eggs are fixed below an incubation frame and placed on the periphery in the rice field, daily egg yolk fries fall on dense meshes of the incubation frame after the fertilized eggs are incubated, and the incubation frame can be withdrawn after the fries swim horizontally and leave the dense meshes; fish fries are caught, wherein during catching, water is drained to enable the fish fries in the rice field to swim back into the fish fry collecting ditch, and then the fish fries are caught through a net; during capturing, capturing is carried out according to defecation of the rice field, and stress reaction caused by oxygen deficit and too high density is prevented; according to the method, natural methods are adopted for rice planting, fertilized egg hatching and fry rearing, the quality of generated fries is good, the survival rate of adult fish culture is high, fry hatching facilities are greatly saved, and the yield and benefits of the rice field per unit area are remarkably increased.

Description

Technical Field

[0001] The invention belongs to the technical field of breeding and cultivation, and particularly relates to a method for hatching fish fertilized eggs and cultivating fish fry by utilizing rice fields. Background Art

[0002] my country is a major aquaculture country in the world and the only country where aquaculture exceeds fishing. The annual aquaculture output is more than 50 million tons, so a large number of fish fry are needed for aquaculture production every year. The fry of aquaculture comes from artificial breeding. The fertilized eggs need to be artificially hatched and fry cultured before they can be used for adult fish breeding. The hatching of fertilized eggs and the cultivation of fry are the key links in aquaculture production. At present, these key links are generally carried out in ponds and hatchery facilities.

[0003] In order to improve the hatching rate and production efficiency of fertilized eggs, incubation generally adopts intensive methods to achieve high-density production under controllable conditions. Under good incubation conditions, the hatching efficiency of fertilized eggs is high and the fry production rate is high. However, due to the delicate incubation method, some fry that should be eliminated are also retained. These fry are deformed, weak or have congenital genetic defects, and have poor resistance to the environment and diseases, resulting in a relatively low survival rate in the later stage of breeding. This is also one of the factors for the current serious outbreak of aquatic fish diseases, causing serious losses to breeding production.

[0004] From the history and reality of aquaculture, it is proved that although the hatching rate of fry hatched under natural ecological environment conditions is relatively low, the quality of fry is good and the survival rate of late aquaculture is high, and there are few fish diseases, which reduces the use of drugs and aquaculture costs, which is very beneficial for aquaculture production. However, if hatching is adopted under natural conditions, a large number of ponds will inevitably be occupied, which will cause high production costs and affect the total output. Generally, this method is rarely used for fry production. In addition, the cultivation of fry from water flower to summer flower stage after hatching is generally carried out in ponds or factory facilities and equipment, because the initial demand for water quality and nutrition of seedling cultivation is high, and a large amount of feed with high nutritional value needs to be fed in the cultivation process of seedling, and the intake rate and digestion and absorption of feed in the seedling stage of fish are not as good as those of adult fish, which often causes the feeding water to be eutrophicated quickly in a short period of time, and the fry is prone to disease and death. At this time, a large amount of water change and water quality improvement are required, and energy consumption is also high. In addition, the method of fertilization cultivates zooplankton as seedling bait, which has a more serious impact on the eutrophication of water quality, and increases the burden of tailwater treatment and the pressure of external discharge. These cultivation methods all occupy a large amount of manpower and material resources, breeding facilities and pond area. Summary of the invention

[0005] The present invention provides a method for hatching fertilized fish eggs and cultivating fish fry by using rice fields, which can solve the drawbacks of occupying a large amount of water surface and equipment, high energy consumption and easy water pollution in the current fish hatching and seedling cultivation process. The present invention can carry out fish hatching and seedling cultivation in rice fields during the fish breeding season, so as to achieve the purpose of promoting rice growth, reducing seedling breeding input and improving product quality.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] The embodiment of the present invention provides a method for hatching fertilized fish eggs and raising fish fry using rice fields, comprising the following steps:

[0008] Step 1, rice field transformation: select a rice field with an area of ​​2 to 5 mu, in addition to raising the ridge, open a seedling collection ditch on one side of the rice field, the seedling collection ditch is required to be 0.6 to 2 meters wide and 40 to 100 centimeters deep. After the seedlings are planted, in order to ensure that the fry can swim back to the seedling collection ditch smoothly when collected, use one end of a slotting device to start from the seedling collection ditch and open a number of shallow trenches with triangular cross sections between the seedlings in the field, and the width of the shallow trench is less than the seedling row spacing;

[0009] Step 2, fertilized egg hatching: deepen the water level of the shallow ditch to 30-40 cm, fix the fish nests with fertilized eggs under the hatching rack, and place them around the rice field, and ensure that the distance between the fish nests is more than two row spacings; after the fertilized eggs are hatched, the yolk seedlings fall on the dense mesh of the hatching rack, and the fry leave the dense mesh after swimming horizontally, and the hatching rack can be withdrawn at this time;

[0010] Step 3, fry cultivation: no feed is given in the first 5 to 7 days after the fry swims horizontally, and fine rice bran or wheat bran is fed after 7 days, and fermented chicken manure mixed liquid fertilizer is applied once every 7 weeks; the chicken manure liquid fertilizer is soaked before use, and the supernatant is added with inorganic phosphorus fertilizer or potassium fertilizer for dissolution and then applied; after 15 days, feed is given in the fry collection ditch, and the fry is cultivated for 1 to 2 months. The fry can grow into summer flower fry, and the feeding is done by a feeder;

[0011] Step 4, catching fry: After being raised for 1 to 2 months, the body length of water flower fish fry can reach 5 to 15 cm, and they can be caught for sale or for large-sized fish breeding; when fishing, drain the water to make the fish in the rice field return to the fry collection ditch, and then catch them with a net; when catching, catch them according to the defecation of the rice field to prevent stress reactions caused by lack of oxygen and excessive density.

[0012] An optional embodiment of the present invention, step 1, the groover includes a main board and a plurality of splitting pieces; the main board includes a raised head and a rectangular board surface, a triangular second cutting piece is arranged at the back end of the board surface, a strip-shaped first cutting piece and a plurality of splitting pieces are also arranged on the back of the board surface, the first cutting piece is arranged perpendicular to the second cutting piece, the first cutting piece ensures the linear movement of the board surface, the second cutting piece cuts the paddy field bottom mud into triangular strips, and then the splitting pieces separate the paddy field bottom mud on both sides of the main board, thereby forming a shallow groove.

[0013] In an optional embodiment of the present invention, the slotting tool in step 1 also includes a force-bearing arm, which includes a handle, a fixing rod and a fixing frame, wherein the fixing frame is fixed to the front end of the main board, the handle is fixed to the fixing frame, the fixing rod is at the rear end of the main board, and the fixing rod is also fixed to the handle, and the position of the handle on the fixing rod is adjustable, thereby changing the angle of the handle to facilitate manual or mechanical operation.

[0014] In an optional embodiment of the present invention, the fish nest in step 2 is made of palm flakes and mesh.

[0015] In an optional embodiment of the present invention, the hatching rack in step 2 is used to place fish nests, and the hatching rack includes a fixed frame, a dense mesh and a hook. The fish nest is placed on the dense mesh. The fixed frame is a gate-shaped beam structure. A hook is arranged on the fixed frame, and the hook is used to fix the fish nest. The dense mesh is fixed between the vertical rods on both sides of the fixed frame by screws. When not in use, the two are put together. When in use, the fixed frame is opened, and the lower ends of the vertical rods of the fixed frame are inserted into the soil, so that the dense mesh is parallel to and in contact with the bottom surface of the rice field, and the distance between the dense mesh and the beam of the fixed frame is maintained at 8 to 12 centimeters.

[0016] In an optional embodiment of the present invention, the hatching capacity of fertilized eggs per acre in step 2 is 200,000 to 300,000.

[0017] In an optional embodiment of the present invention, the feeder of step 3 includes a hopper, a water pump, a conduit, a vertical pipe ball valve and a pressure valve; the hopper is used to hold soy milk, rice bran or wheat bran suspension or liquid fertilizer; a water pump is connected under the hopper, the water pump transports liquid to the conduit, the end of the conduit is connected to a vertical pipe, the open end of the vertical pipe becomes smaller, and a float is provided inside the vertical pipe. When the liquid in the vertical pipe reaches the top, the float will seal the opening, so that the pipe is isobaric and filled with liquid; under the action of the pumping force of the water pump, the pressure in the conduit increases, and when the pressure reaches a certain level, the pressure valve on the conduit will be opened, so that the liquid is sprayed out along each pressure valve on the conduit to achieve uniform feeding or fertilization, and the pressure valve is connected to the conduit.

[0018] In an optional embodiment of the present invention, the pressure valve includes a piston cylinder, a piston, a pressure spring and a connecting pipe, the connecting pipe is connected to the piston cylinder, the piston in the piston cylinder is connected to the pressure spring, the liquid in the conduit transfers the pressure to the piston cylinder through the connecting pipe, the pressure spring is compressed by the piston, a hole is provided on the wall of the piston cylinder, when the pressure in the piston cylinder reaches a preset value, the hole on the piston cylinder is exposed, and liquid is ejected.

[0019] Beneficial effects: The embodiment of the present invention provides a method for hatching fertilized fish eggs and cultivating fry using rice fields, including rice field transformation, fertilized egg hatching, fry cultivation, feeding and fertilizing, and fry catching; fertilized egg hatching: deepen the water level of the shallow ditch to 30-40 cm, fix the fish nests with fertilized eggs attached under the hatching rack, and place them around the rice field. After the fertilized eggs are hatched, the yolk seedlings fall on the dense mesh of the hatching rack, and the fry leave the dense mesh after swimming horizontally, and the hatching rack can be withdrawn at this time; fry catching: when fishing, drain the water to make the fish in the rice field return to the seedling collection ditch, and then catch them with a net; when catching, catch according to the defecation of the rice field to prevent stress reactions caused by hypoxia and excessive density; the rice planting, fertilized egg hatching and fry cultivation of the present invention all adopt natural methods, the fry produced are of good quality, the survival rate of adult fish is high, the fry hatching facilities are greatly saved, and the output and benefits of rice fields per unit area are significantly increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A flow chart of a method for hatching fertilized fish eggs and cultivating fry using rice fields provided in an embodiment of the present application.

[0022] Figure 2 A schematic diagram of the structure of a slotting device used in a method for hatching fertilized fish eggs and raising fry in rice fields provided in an embodiment of the present application.

[0023] Figure 3 A schematic diagram of the mainboard structure of a slotting device provided in an embodiment of the present application.

[0024] Figure 4 A schematic diagram of a slicing structure of a slotting device provided in an embodiment of the present application.

[0025] Figure 5A schematic diagram of the structure of a hatching rack used in a method for hatching fertilized fish eggs and raising fry in rice fields provided in an embodiment of the present application.

[0026] Figure 6 A schematic diagram of the pressure valve structure of a feeder used in a method for hatching fertilized fish eggs and cultivating fry in rice fields provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0028] like Figure 1 As shown, an embodiment of the present invention provides a method for hatching fertilized fish eggs and cultivating fish fry using rice fields, including rice field transformation, fertilized egg hatching, fish fry cultivation, feeding and fertilizing, and fish fry catching. Fish fry hatching and cultivation can be carried out in rice fields, thereby achieving the purpose of saving ponds, ecological seedling cultivation, promoting rice growth and realizing fish fry cultivation.

[0029] A method for hatching fish fertilized eggs and raising fish fry using rice fields has the following specific steps:

[0030] Step 1, rice field transformation: select a rice field with an area of ​​2 to 5 mu, in addition to raising the ridge, open a seedling collection ditch on one side of the rice field, the seedling collection ditch is required to be 0.6 to 2 meters wide and 40 to 100 centimeters deep. After the seedlings are planted, in order to ensure that the fry can swim back to the seedling collection ditch smoothly when collected, use one end of a slotting device to start from the seedling collection ditch and open a number of shallow trenches with triangular cross sections between the seedlings in the field, and the width of the shallow trench is less than the seedling row spacing;

[0031] Step 2, fertilized egg hatching: deepen the water level of the shallow ditch to 30-40 cm, fix the fish nests with fertilized eggs under the hatching rack, and place them around the rice field, and ensure that the distance between the fish nests is more than two row spacings; after the fertilized eggs are hatched, the yolk seedlings fall on the dense mesh of the hatching rack, and the fry leave the dense mesh after swimming horizontally, and the hatching rack can be withdrawn at this time;

[0032] Step 3, fry cultivation: no feed is given in the first 5 to 7 days after the fry swims horizontally, and fine rice bran or wheat bran is fed after 7 days, and fermented chicken manure mixed liquid fertilizer is applied once every 7 weeks; the chicken manure liquid fertilizer is soaked before use, and the supernatant is added with inorganic phosphorus fertilizer or potassium fertilizer for dissolution and then applied; after 15 days, feed is given in the fry collection ditch, and the fry is cultivated for 1 to 2 months. The fry can grow into summer flower fry, and the feeding is done by a feeder;

[0033] Step 4, fish fry catching: After 1-2 months of feeding, the body length of water flower fish fry can reach 5-15 cm summer flower fish fingerlings, which can be caught and sold or cultivated into large-sized fish fingerlings; when catching, drain the water to make the fish fingerlings in the rice field return to the seedling collection ditch, and then catch them with a net; when catching, catch them according to the defecation of the rice field to prevent the stress response caused by lack of oxygen and high density. In this embodiment, multiple defecation arrays are set in the rice field.

[0034] like Figure 2 , Figure 3 and Figure 4 As shown, in step 1, the slotting device includes a main board 1 and a splitting sheet 2; the main board 1 includes a raised head 1-1 and a rectangular board surface 1-2, a triangular second cutting sheet 7 is arranged at the back end of the board surface 1-2, and a strip-shaped first cutting sheet 6 and a plurality of splitting sheets 2 are also arranged on the back of the board surface 1-2, the first cutting sheet 6 is arranged perpendicular to the second cutting sheet 7, the first cutting sheet 6 ensures the straight movement of the board surface 1-2, the second cutting sheet 7 cuts the paddy field bottom mud into triangular strips, and then is separated by the splitting sheet 2 on both sides of the main board 1, thereby forming a shallow groove. Each splitting sheet 2 includes a right-angle side 2-1 and a hypotenuse 2-2.

[0035] Step 1: The slotting tool also includes a force-bearing arm, which includes a handle 5, a fixing rod 4 and a fixing frame 3. The fixing frame 3 is fixed to the front end of the main board 1, the handle 5 is fixed to the fixing frame 4, the fixing rod 4 is at the rear end of the main board 1, and the fixing rod 4 is also fixed to the handle 5. The position of the handle 5 on the fixing rod 4 is adjustable, thereby changing the angle of the handle 5 to facilitate manual or mechanical operation.

[0036] like Figure 5 As shown, the fish nest of step 2 is a palm leaf and a mesh. The hatching rack of step 2 is used to place the fish nest. The hatching rack includes a fixed frame 8, a dense mesh 9 and a hook 10. The fish nest is placed on the dense mesh 9. The fixed frame 8 is a gate-shaped beam structure. The fixed frame 8 is provided with a hook 10, which is used to fix the fish nest; the dense mesh 9 is fixed between the vertical bars on both sides of the fixed frame 8 by screws 11. When not in use, the two are put together. When in use, the fixed frame 8 is opened, and the lower end of the vertical bar of the fixed frame 8 is inserted into the soil, so that the dense mesh 9 is parallel to and in contact with the bottom surface of the rice field, and the distance between the dense mesh 9 and the beam of the fixed frame 8 is maintained at 8 to 12 cm, preferably 10 cm. The hatching capacity of fertilized eggs per mu in step 2 is 200,000 to 300,000.

[0037] The feeder of step 3 comprises a hopper, a water pump, a conduit, a vertical pipe ball valve and a pressure valve; the hopper is used to hold soybean milk, rice bran or wheat bran suspension or liquid fertilizer, a water pump is connected under the hopper, the water pump transports liquid to the conduit, the end of the conduit is connected to a vertical pipe, the opening end of the vertical pipe becomes smaller, a float is arranged inside the vertical pipe, when the liquid in the vertical pipe reaches the top, the float will seal the opening, so that the pipe is isobaric and filled with liquid; under the action of the pumping force of the water pump, the pressure in the conduit increases, when the pressure reaches a certain level, the pressure valve on the conduit will be opened, so that the liquid will be sprayed out along each pressure valve on the conduit, so as to achieve uniform feeding or fertilization, and the pressure valve is connected to the conduit.

[0038] like Figure 6 As shown, the pressure valve includes a piston cylinder 12, a piston 13, a pressure spring 15 and a connecting pipe 14. The connecting pipe 14 is connected to the piston cylinder 12. The piston 13 in the piston cylinder 12 is connected to the pressure spring 15. The liquid in the conduit transmits the pressure to the piston cylinder 12 through the connecting pipe 14. The pressure spring is compressed by the piston 13. A hole 16 is provided on the wall of the piston cylinder 12. When the pressure in the piston cylinder 12 reaches a preset value, the hole 16 on the piston cylinder 12 is exposed and the liquid is ejected.

[0039] Example 1

[0040] There are 5 rice fields with an area of ​​2.5 mu / mouth, which are used to hatch fertilized eggs of carp in rice fields and cultivate fry, according to the technical scheme of the method of using rice fields to hatch fertilized eggs of fish and cultivate fry. Rice field transformation: Select a rice field with an area of ​​about 2.5 mu. In addition to raising the ridge, open a seedling collection ditch on one side of the rice field. The seedling collection ditch is required to be about 1 meter wide and 50 cm deep. After the seedlings are planted, in order to ensure that the fry can swim back to the seedling collection ditch smoothly when they are collected, use one end of the slot opener to start from the seedling collection ditch and open several shallow trenches with triangular cross sections between the seedlings in the field. The width of the shallow trench is less than the spacing between the seedling rows. Fertilized egg hatching: Deepen the water level to 40 cm, and place the fish nests attached with fertilized eggs, generally palm leaves, mesh sheets, etc. Fix the fish nests under the hatching rack and place them around the rice field. The distance between the nests is guaranteed to be more than two row spacings. The hatching capacity of fertilized eggs per mu is 200,000 to 300,000.

[0041] Results: The hatching rate of fertilized carp eggs averaged over 90%, and the survival rate of carp in the summer fingerling stage was over 95%. The carp were strong and healthy, and there were few diseases in the later adult fish breeding, which significantly increased the output and benefits per unit area of ​​rice fields.

[0042] Example 2

[0043] There are 3 rice fields with an area of ​​5 mu / mouth, which are in good condition. The fertilized eggs of crucian carp in the rice fields are prepared to be hatched and the seedlings are cultivated according to the technical scheme of the method of using rice fields for hatching fertilized eggs and cultivating fish fry. Rice field transformation: Select a rice field with an area of ​​about 5 mu. In addition to raising the ridge, open a seedling collection ditch on one side of the rice field. The seedling collection ditch is required to be about 1 meter wide and 50 cm deep. After the seedlings are planted, in order to ensure that the fry can swim back to the seedling collection ditch smoothly when they are collected, use one end of the slot opener to start from the seedling collection ditch and open several shallow trenches with triangular cross sections between the seedlings in the field. The width of the shallow trench is less than the spacing between the seedling rows. Fertilized egg hatching: Deepen the water level to 40 cm, and put the fish nests attached with fertilized eggs, generally palm leaves, mesh, etc. Fix the fish nests under the hatching rack and place them around the rice field. The distance between the nests is guaranteed to be more than two row spacings. The hatching capacity of fertilized eggs per mu is about 300,000.

[0044] Results: The hatching rate of fertilized eggs of crucian carp averaged over 95%, and the survival rate of the fish in the summer fingerling stage was over 98%. The fish were strong and healthy, and there were few diseases in the later adult fish farming, which significantly increased the output and benefits per unit area of ​​rice fields.

[0045] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A method for hatching fish fertilized eggs and raising fish fry using rice fields, characterized in that: The following steps are involved: Step 1, rice field transformation: select a rice field with an area of ​​2 to 5 mu, in addition to raising the ridge, open a seedling collection ditch on one side of the rice field, the seedling collection ditch is required to be 0.6 to 2 meters wide and 40 to 100 centimeters deep. After the seedlings are planted, in order to ensure that the fry can swim back to the seedling collection ditch smoothly when collected, use one end of a slotting device to start from the seedling collection ditch and open a number of shallow trenches with triangular cross sections between the seedlings in the field, and the width of the shallow trench is less than the seedling row spacing; Step 2, fertilized egg hatching: deepen the water level of the shallow ditch to 30-40 cm, fix the fish nests with fertilized eggs under the hatching rack, and place them around the rice field, and ensure that the distance between the fish nests is more than two row spacings; after the fertilized eggs are hatched, the yolk seedlings fall on the dense mesh of the hatching rack, and the fry leave the dense mesh after swimming horizontally, and the hatching rack can be withdrawn at this time; Step 3, fry cultivation: no feed is given in the first 5 to 7 days after the fry swims horizontally, and fine rice bran or wheat bran is fed after 7 days, and fermented chicken manure mixed liquid fertilizer is applied once every 7 weeks; the chicken manure liquid fertilizer is soaked before use, and the supernatant is added with inorganic phosphorus fertilizer or potassium fertilizer for dissolution and then applied; after 15 days, feed is given in the fry collection ditch, and the fry is cultivated for 1 to 2 months. The fry can grow into summer flower fry, and the feeding is done by a feeder; Step 4, catching fry: After being raised for 1 to 2 months, the body length of water flower fish fry can reach 5 to 15 cm, and they can be caught for sale or for large-sized fish breeding; when fishing, drain the water to make the fish in the rice field return to the fry collection ditch, and then catch them with a net; when catching, catch them according to the defecation of the rice field to prevent stress reactions caused by lack of oxygen and excessive density.

2. The method for hatching fish fertilized eggs and raising fish fry using rice fields according to claim 1, characterized in that: Step 1: The slotting tool includes a main board and a plurality of splitting pieces; the main board includes a raised head and a rectangular board surface, a triangular second cutting piece is arranged at the back end of the board surface, a strip-shaped first cutting piece and a plurality of splitting pieces are also arranged on the back of the board surface, the first cutting piece is arranged perpendicular to the second cutting piece, the first cutting piece ensures the linear movement of the board surface, the second cutting piece cuts the paddy field bottom mud into triangular strips, and then the splitting pieces separate the paddy field bottom mud on both sides of the main board, thereby forming a shallow groove.

3. The method for hatching fish fertilized eggs and raising fish fry using rice fields according to claim 2, characterized in that: Step 1: The slotting tool also includes a force-bearing arm, which includes a handle, a fixing rod and a fixing frame. The fixing frame is fixed to the front end of the main board, the handle is fixed to the fixing frame, the fixing rod is at the rear end of the main board, and the fixing rod is also fixed to the handle. The position of the handle on the fixing rod is adjustable, thereby changing the angle of the handle to facilitate manual or mechanical operation.

4. The method for hatching fish fertilized eggs and raising fish fry using rice fields according to claim 1, characterized in that: The fish nest in step 2 is made of palm pieces and mesh.

5. The method for hatching fish fertilized eggs and raising fish fry using rice fields according to claim 1, characterized in that: The hatching rack in step 2 is used to place fish nests. The hatching rack includes a fixed frame, a dense mesh and a hook. The fish nest is placed on the dense mesh. The fixed frame is a gate-shaped beam structure. A hook is arranged on the fixed frame, and the hook is used to fix the fish nest. The dense mesh is fixed between the vertical rods on both sides of the fixed frame by screws. When not in use, the two are put together. When in use, the fixed frame is opened, and the lower end of the vertical rod of the fixed frame is inserted into the soil, so that the dense mesh is parallel to and in contact with the bottom surface of the rice field, and the distance between the dense mesh and the beam of the fixed frame is maintained at 8 to 12 cm.

6. The method for hatching fertilized fish eggs and raising fry in rice fields according to claim 1, characterized in that: The hatching capacity of fertilized eggs per acre in step 2 is 200,000 to 300,000.

7. The method for hatching fertilized fish eggs and raising fry in rice fields according to claim 1, characterized in that: The feeder of step 3 comprises a hopper, a water pump, a conduit, a vertical pipe ball valve and a pressure valve; the hopper is used to hold soybean milk, rice bran or wheat bran suspension or liquid fertilizer; a water pump is connected under the hopper, the water pump transports liquid to the conduit, the end of the conduit is connected to a vertical pipe, the open end of the vertical pipe becomes smaller, and a float is arranged inside the vertical pipe. When the liquid in the vertical pipe reaches the top, the float seals the opening, so that the pipe is isobaric and filled with liquid; under the action of the pumping force of the water pump, the pressure in the conduit increases, and when the pressure reaches a certain level, the pressure valve on the conduit is opened, so that the liquid is sprayed out along each pressure valve on the conduit, so as to achieve uniform feeding or fertilization, and the pressure valve is connected to the conduit.

8. The method for hatching fish fertilized eggs and raising fish fry using rice fields according to claim 7, characterized in that: The pressure valve includes a piston cylinder, a piston, a pressure spring and a connecting pipe, wherein the connecting pipe is connected to the piston cylinder, and the piston in the piston cylinder is connected to the pressure spring. The liquid in the conduit transmits the pressure to the piston cylinder through the connecting pipe, and the pressure spring is compressed by the piston. A hole is provided on the wall of the piston cylinder. When the pressure in the piston cylinder reaches a preset value, the hole on the piston cylinder is exposed and the liquid is sprayed out.

Images