A cultivation method for improving the survival rate of clownfish seedlings

Abstract

The present invention relates to a cultivation method for improving the survival rate of clownfish seedlings, including aquaculture water and equipment management, fertilized egg hatching treatment, larval stage cultivation management, and juvenile stage cultivation management. The specific operations include the following contents: (1) aquaculture water and equipment management, including the preparation of aquaculture water and the treatment of aquaculture equipment; (2) fertilized egg hatching treatment; (3) larval stage cultivation management, including water change management, bait feeding management, drug prevention, and aeration management; (4) juvenile stage cultivation management; and (5) juvenile stage cultivation management. The present invention performs differentiated aquaculture management on clownfish seedlings at different growth stages, and by adjusting the aquaculture environment, water quality, and feeding feed at each cultivation stage, effectively prevents and treats amyloidosis and dinoflagellate disease, and reduces damage to the fish body caused by other parasites and fungi; thereby ensuring a clean living environment for the clownfish and effectively improving the survival rate of the clownfish.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture, in particular to a clownfish fry and larvae breeding technology, and in particular to a breeding method for improving the survival rate of clownfish fry. Background Art

[0002] Clownfish, also known as anemonefish, belong to the family Pomacentridae and genus Amphiprion. They are adorable little creatures of the coral reef, with their beautiful colors and gentle temperament. They have become one of the most popular ornamental fish and have broad market prospects. Several clownfish species have been successfully bred in captivity, but large-scale production is limited, in part due to low larval survival rates caused by diseases, particularly the severe amyloidosis.

[0003] Amylodinium disease, a fish disease caused by the dinoflagellate Mylodinium eyespot, harms a wide range of marine and ornamental fish. Affected fish exhibit numerous aggregates of the dinoflagellate Mylodinium eyespot, appearing as white spots on their gills, skin, and fins. This disease, also known as "white spot disease," initially manifests as restlessness and rubbing of the body, followed by rapid breathing and a grayish-white discoloration of the gills. The disease spreads rapidly across multiple clownfish species, from larvae to adults. Mortality rates can reach 100% for larvae and over 90% for juveniles. It is difficult to cure and prone to recurrence.

[0004] Therefore, in the artificial breeding process of clownfish, effective prevention and control of starch egg dinoflagellate disease has become an urgent problem that needs to be solved in order to improve the survival rate of clownfish seedlings and realize their large-scale breeding. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defect of high mortality of clownfish larvae and fry due to starch egg dinoflagellate disease in the existing breeding process of clownfish, provide a breeding method for improving the survival rate of clownfish fry in a tank breeding mode in a workshop, and reduce the mortality rate of artificially bred clownfish larvae and fry.

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] A method for improving the survival rate of clownfish fry includes the following steps: managing aquaculture water and equipment, incubating fertilized eggs, managing larval stage cultivation, managing juvenile stage cultivation, and managing juvenile and young stage cultivation.

[0008] (1) Management of aquaculture water and equipment, including the preparation of aquaculture water and the handling of aquaculture equipment;

[0009] (2) Fertilized egg incubation: Use a formalin solution with a concentration of 200 mg / L to soak the fertilized eggs and the attachment substrate for 10 minutes. During this period, aeration is used to maintain the dissolved oxygen content of the water at 5-6 mg / L. Add enough aquaculture water to the tank to just soak the fertilized egg attachment substrate, and place aeration stones. Transfer the treated attachment substrate with the fertilized eggs to the prepared tank for incubation in the dark.

[0010] (3) Frying management, including water change management, feed management, drug prevention and aeration management; water change management: 24 hours after the fry ruptures, add new water to fill the tank; then during the breeding process, change the water every 24 hours, and the single water change volume is 1 / 2 of the water capacity of the tank; feed management: newly hatched fry are fed with ss-type rotifers combined with seawater chlorella, and the fed rotifers must be treated with 80 mg / L formalin and 5 mg / L oxytetracycline for 4-8 hours and filtered through 400 mesh special gauze; drug prevention: according to the actual volume of water in the tank, formalin is added to make the final concentration of the drug solution 15.75 g / m 3 The amount of formalin added after the water change operation is calculated as follows: water change volume × 15.75 g / m 3 Calculation; Aeration management: maintain dissolved oxygen in aquaculture water at around 5.5 mg / L;

[0011] (4) Frying stage cultivation management, including water change management, bait feeding management, drug prevention and aeration management; wherein the drug prevention method is the same as that in the larval stage cultivation management; the water change management: water is changed every 24 hours during the fry stage, and the single water change volume is 1 / 2 of the water capacity of the tank; bait feeding management: newly hatched Artemia eggs are used for feeding, and the Artemia larvae fed must be treated with 80 mg / L formalin and 5 mg / L oxytetracycline for 4-8 hours and filtered through a 150-200 mesh special gauze; aeration management: the dissolved oxygen in the aquaculture water is maintained at about 6 mg / L;

[0012] (5) Cultivation and management of juvenile fish, including water flow management, feed management and drug prevention; water flow management: after the fertilized eggs break the membrane, they spend about 4 weeks in the tank. When the average body length of the fry is greater than 0.8-1.0 cm, they are moved into the circulating water tank for breeding. The initial water flow rate is adjusted to 5L / min. As the adaptability of the fry increases, the flow rate is appropriately increased, but it needs to be gradually increased and not more than 10L / min; feed management: the fry are gradually acclimated to eat artificial compound feed, and are fed twice a day in the morning and evening; drug prevention: the fry and the circulating water system are bathed in formalin once every two weeks. Specifically, formalin is added according to the actual volume of the water in the circulating water culture system to make the final concentration of the drug solution 80g / m 3After 4-6 hours of circulating immersion, drain about 4 / 5 of the old water in the tank and add appropriate new water; the dissolved oxygen is maintained above 5.5 mg / L during the bath.

[0013] Moreover, the larval stage cultivation management and the juvenile stage cultivation management and the juvenile stage cultivation management all include daily management and inspection, and the specific contents are as follows:

[0014] Daily management: Clean the bottom and walls of the tank at a fixed time every morning, using a dedicated and special sewage suction device to absorb the dirt on the entire tank wall using the siphon principle;

[0015] Inspection: Use a bright yellow flashlight with good reflectivity to carefully observe the surface of the fry for white spots three times a day, morning, noon and evening, to promptly identify fry with darker body color and abnormal behavior, and perform microscopic examination on their gills, epidermis and other tissues to determine the occurrence of starch egg dinoflagellate disease; isolate symptomatic individuals in a timely manner and provide individual treatment.

[0016] Moreover, the tank is a small indoor hatching and breeding device for clownfish, and the outer surface thereof is adhered with opaque wallpaper.

[0017] Moreover, the aquaculture water is obtained by using tap water, filtering to remove impurities, ultraviolet sterilization, ion exchange softening, and adding imported sea crystal.

[0018] Moreover, the treatment of the breeding tools: the main process is to first brush the tank, air pipe, air stone and sewage suction tool used in the breeding plan, and then use a concentration of 30g / m 3 Spray the surface of the equipment with potassium permanganate solution evenly for routine disinfection, and leave it overnight. Rinse it three times with aquaculture water the next day, then drain and set aside. Repeat the above operation process after each use of the aquaculture equipment to prepare for subsequent aquaculture use. If the aquaculture equipment is used in an aquaculture environment where amylocyanine disease has recently broken out, it is necessary to use a 300g / m 3 Spray the surface of the equipment with formalin solution and cover it with plastic film overnight for 6-12 hours, then use the above conventional treatment.

[0019] Moreover, the new water is aquaculture water and is obtained after passing through filter cotton, protein separator, ultraviolet sterilization, aeration and temperature adjustment in sequence.

[0020] Moreover, the water changing operation adopts a specialized and dedicated sewage suction device, which uses the siphon principle to discharge 1 / 2 volume of old water in the breeding tank and add an equal amount of new water at the same temperature.

[0021] Moreover, when adding an equal amount of new water of the same temperature during the water change process, the operation must be gentle, without causing too much impact on the fry, and without stirring the bottom of the tank. A special water spoon or measuring cup or other container is preferably used to immerse the entire container filled with water in the tank. When the water surfaces inside and outside the container are in the same plane, the container is rotated, the container mouth is tilted downward, and then gently pulled out of the tank; and the sewage suction device used in the water change process must have the function of adjusting the water flow size to prevent the fry from being accidentally sucked in. The sewage suction operation needs to be gentle and the bottom of the tank should not be excessively stirred.

[0022] Moreover, the time period for cleaning the bottom and wall of the tank in the daily management is after feeding.

[0023] Moreover, the tool used for spraying in the treatment of the breeding tools is a spray pot; the specific operation is to put all the breeding tools into the tank and spray the medicine.

[0024] The advantages and positive effects of the present invention are:

[0025] The present invention respectively takes into account the water change management, drug prevention, bait feeding management, and aeration management in the fertilized egg hatching process, larval cultivation management, and late larval cultivation management. By adjusting the breeding environment including sewage suction, water change, and aeration, using drugs such as potassium permanganate and formalin, and scientifically processing and replacing bait, the present invention effectively prevents the outbreak of starch egg dinoflagellate disease during the breeding process, reduces the reproduction and spread of other parasites and fungi, effectively improves the survival rate of clownfish seedlings, and lays a foundation for the large-scale development of the clownfish industry. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and through specific embodiments. The following embodiments are merely illustrative and non-restrictive, and the scope of protection of the present invention cannot be limited thereto.

[0027] A method for improving the survival rate of clownfish fry includes the following steps: managing aquaculture water and equipment, incubating fertilized eggs, managing larval stage cultivation, managing juvenile stage cultivation, and managing juvenile and young stage cultivation.

[0028] (1) Management of aquaculture water and equipment, including the preparation of aquaculture water and the handling of aquaculture equipment;

[0029] The aquaculture water is prepared by using tap water, which is filtered to remove impurities, sterilized by ultraviolet light, softened by ion exchange, and then added with imported sea crystals;

[0030] The treatment of the breeding tools is mainly to brush the tank, air pipe, air stone and sewage suction tool used in the breeding plan, and then use 30g / m 3Evenly spray the surface with potassium permanganate solution for routine disinfection, then rinse with aquaculture water for 3 times, control and set aside. The above operation process needs to be repeated after the use of aquaculture tools to prepare for subsequent aquaculture use. If the aquaculture tools are used in an aquaculture environment where starch egg dinoflagellate disease has recently broken out, they need to be cleaned and then firstly use a solution with a concentration of 300g / m 3 The surface of the tool is sprayed with a formalin solution and covered with a plastic film overnight, and then the conventional treatment is performed. The potassium permanganate solution is obtained by mixing 300 mg of potassium permanganate powder into 10 L of fresh water and mixing well; the formalin solution is obtained by mixing 3 ml of formalin into 10 L of aquaculture water and mixing well; the spraying tool is a spray bottle; the concentration is 300 g / m 3 The specific operation of treating breeding tools with formalin solution is: put all breeding tools into the tank, spray the medicine, and then directly cover the tank with plastic film overnight for 6-12 hours.

[0031] (2) Fertilized egg incubation: Before transferring the fertilized eggs and their attachment base to the tank, soak the fertilized eggs and their attachment base in a formalin solution with a concentration of 200 mg / L for 10 minutes. During this period, aeration is used to maintain the dissolved oxygen content of the water at 5-6 mg / L. At the same time, the aeration bubbles are required to cause the fertilized eggs to sway slightly. Before transferring the fertilized eggs, add fresh water to the tank in advance that just covers the attachment base of the fertilized eggs, and place aeration stones. Finally, transfer the treated attachment base with the fertilized eggs to the prepared tank for incubation in the dark.

[0032] (3) Larval cultivation and management, including water change management, feed feeding management, drug prevention, aeration management, daily management and inspection;

[0033] For water change management, 24 hours after the fry rupture their membranes, new water is added to fill the tank. This new water is obtained by filtering with filter cotton, removing pollutants with a protein skimmer, sterilizing with ultraviolet light, aerating with an air pump, and adjusting the temperature with air conditioning. Subsequently, during the breeding process, water changes are performed every 24 hours. The water change operation uses a dedicated and special sewage suction device to drain 1 / 2 of the tank volume by siphoning, and then add an equal amount of new water at the same temperature.

[0034] The bait feeding management includes feeding newly hatched fry with SS-type rotifers in combination with marine chlorella. The rotifers are treated with 80 mg / L formalin and 5 mg / L oxytetracycline for 4-8 hours and filtered through 400-mesh special gauze to remove impurities and liquid medicine before use. This is to eliminate or kill starch dinoflagellates and other pathogens that may be carried in the bait.

[0035] Drug prevention: According to the actual volume of water in the tank, add formalin to make the final concentration of the drug solution 15.75g / m 3The amount of formalin added after the water change operation is calculated as follows: water change volume × 15.75 g / m 3 calculate;

[0036] Aeration management: Maintain the dissolved oxygen level in the aquaculture water at around 5.5 mg / L. The aeration intensity should be such that the fry do not experience severe up and down shocks.

[0037] (4) Cultivation and management of juvenile fish:

[0038] The juvenile stage cultivation management includes water change management, bait feeding management, drug prevention, aeration management, daily management and inspection; wherein the drug prevention is the same as the larval stage management;

[0039] The water change management: water change operation is carried out every 24 hours when the juvenile fish enter the stage, that is, a special and dedicated sewage suction device is used to discharge 1 / 2 volume of old water in the breeding tank by siphon principle, and an equal amount of new water of the same temperature is added;

[0040] Feed management: Use newly hatched Artemia eggs for feeding. The Artemia larvae must be treated with 80mg / L formalin and 5mg / L oxytetracycline for 4-8 hours and filtered through 150-200 mesh special gauze to remove impurities and liquid medicine before use. The purpose is to eliminate or kill starch egg dinoflagellates and other pathogens that may be carried in the bait;

[0041] Aeration management: Maintain the dissolved oxygen level in the aquaculture water at around 6 mg / L. The aeration intensity should be such that the fry do not experience severe up and down shocks.

[0042] (5) Cultivation and management of juvenile fish:

[0043] The juvenile fish cultivation management includes water flow management, feeding management, drug prevention, daily management and inspection. The water flow management is as follows: after the fertilized eggs rupture, they spend about 4 weeks in the tank. When the fry have an average body length of more than 0.8-1.0 cm, are strong, and have further enhanced swimming ability, they can be moved into the circulating water tank for cultivation. The initial water flow rate is adjusted to 5 L / min. As the juvenile fish's adaptability increases, the flow rate can be appropriately increased, generally not exceeding 10 L / min.

[0044] Feeding management: gradually acclimate the seedlings to artificial compound feed, feeding them twice a day in the morning and evening;

[0045] Drug prevention: The seedlings are bathed in formalin in the circulating water system of the circulating water tank every two weeks and the water is replaced with new water. The specific method is as follows: according to the actual volume of water in the circulating water aquaculture system, formalin is added to make the final concentration of the solution 80g / m 3After 4-6 hours of circulating immersion, drain about 4 / 5 of the volume of the tank's water capacity and add appropriate new water; during the bathing period, the dissolved oxygen is maintained above 5.5 mg / L.

[0046] The above-mentioned larval stage cultivation management and juvenile stage cultivation management, as well as the daily management and inspection in the juvenile stage cultivation management are the same, and the specific contents are as follows:

[0047] Daily management: Clean the bottom and walls of the tank at a fixed time every morning, using a dedicated and special sewage suction device to absorb the dirt on the entire tank wall using the siphon principle;

[0048] Inspection: Use a bright yellow flashlight with good reflectivity to carefully observe the surface of the fry for white spots three times a day, morning, noon and evening, to promptly identify fry with darker body color and abnormal behavior, and perform microscopic examination on their gills, epidermis and other tissues to determine the occurrence of starch egg dinoflagellate disease; isolate symptomatic individuals in a timely manner and provide individual treatment.

[0049] The tank is a small indoor hatching and breeding device for clownfish, 40 cm long, 30 cm wide, and 30 cm deep. It is made of 8 mm thick tempered glass and has opaque wallpaper on the outside. The formalin is analytical grade and has a formaldehyde (CHO) content of 37% to 40%.

[0050] When adding an equal amount of new water of the same temperature during the above-mentioned water change operation, the operation must be gentle, without causing too much impact on the fry, and without stirring the bottom of the tank. It is preferred to use a special water scoop or measuring cup and other containers. Immerse the entire container filled with water in the tank. When the water surfaces inside and outside the container are on the same plane, rotate the container, tilt the container mouth downward, and then gently pull it out of the tank. The sewage suction device used in the water change process should preferably have the function of adjusting the water flow size and can effectively prevent the fry from being accidentally sucked in. The sewage suction operation needs to be gentle and the bottom of the tank should not be stirred excessively.

[0051] Among them, in daily management, the cleaning of the bottom and walls of the tank should preferably be done after feeding to prevent the fry from accidentally ingesting dirt due to hunger; if the production is in an aquaculture environment where the starch egg dinoflagellate disease has just broken out, it is preferred to use aquaculture tools that have been brushed, soaked in a formalin solution with a concentration of 300 mg / L overnight, and rinsed with aquaculture water.

[0052] The determination of the formalin solution concentration and time in the treatment of the above-mentioned breeding tools, the formalin solution concentration and time in the fertilized egg incubation treatment, and the final concentration and time of the drug bath in drug prevention is obtained through the following experimental results; (How does it correspond to the following experiment)

[0053] The specific experiments are as follows:

[0054] The concentration and method of use of formalin for preventing fry disease during the juvenile stage of fish cultivation and management are described below with reference to relevant experiments:

[0055] Experimental Materials

[0056] The experimental materials are seedlings infected with starch ovule dinoflagellate disease, the main characteristics of which are: body length 0.8-1 cm, and starch ovule dinoflagellates clearly attached to the surface of the seedlings.

[0057] Experimental methods

[0058] In an experiment using different concentrations of formalin solution to bathe sick clownfish, the method for measuring the shedding of starch ova and algae from the surface of the sick fish and the mortality of the sick fish at different time points is as follows:

[0059] The formalin concentration gradient used in the experiment was set according to the equal logarithmic interval method. The clownfish with starch egg dinoflagellate disease were treated with medicated baths. The treatment time nodes were set at 10 minutes, 2 hours, 4 hours, 6 hours, and 8 hours, respectively. There were 8 experimental groups in total, including the control group. In each experimental group, 250 diseased juvenile fish were randomly selected and placed in a 30L container. The number of diseased fish before the medicated bath was counted as N1, and the number of remaining live fish after each predetermined medicated bath time node was counted as N2. The fry mortality rate R d The calculation method is (N 1- N2) / N1×100%.

[0060] In addition, 10 diseased juvenile fish samples were taken from each experimental group to participate in the starch egg dinoflagellate shedding rate R t The specific method is to place the tail fin or gill of the juvenile fish under a 4x microscope, and the average number of starch egg dinoflagellates in a single field of view before the drug bath is recorded as N. a After each medicinal bath time point, the average number of starch dinoflagellates in a single field of view at similar sites was recorded as N b , starch egg dinoflagellate shedding rate R t The calculation method is (N a- N b ) / N a ×100%.

[0061] The following method is used to detect the death of clownfish with the same disease after being treated with different medicinal bath conditions for 24 hours due to the recurrence of the disease and the toxic side effects of the medicinal bath:

[0062] The group setting was the same as the above experiment. For each experimental group, 150 diseased fry were randomly selected and placed in a 30L container. The number of live fry after the drug bath experiment at each node was counted as N. a After the drug bath experiment was completed, the number of dead seedlings after 24 hours of normal cultivation in each store was N. b , fry mortality rate R d24 The calculation method is N b / Na ×100%.

[0063] Experimental results

[0064] As can be seen from Table 1, using concentration is that the formalin solution of 50mg / L carries out the medicated bath for 8h to sick fry, and the starch egg dinoflagellate shedding effect is not very ideal. If the medicated bath time is extended again at this concentration, the production management process is greatly affected. Using concentration is that the formalin solution of 80mg / L medicated bath is more than 4h, and the shedding rate of starch egg dinoflagellate can reach more than 90%, which is effective. From Table 2 data, we know that using concentration is that the formalin solution of 80mg / L medicated bath is sick fry 8h, or using concentration is that the formalin solution of 130mg / L medicated bath is sick fry more than 2h, which will cause the loss of part fry. Therefore, the concentration preferred 80mg / L that formalin is adopted to carry out disease prevention in the juvenile fish stage, and the preferred 4-6h of processing time.

[0065] Table 1. Shedding of starch ova and dinoflagellates in diseased clownfish under different medicinal bath conditions

[0066]

[0067]

[0068] Table 2 Death of diseased clownfish under different medicated bath conditions

[0069]

[0070] Note: Mortality rate during medicated bath = total number of dead fry at each medicated bath time point ÷ total number of fry before medicated bath operation × 100%.

[0071] The method of using formalin to treat rotifers and Artemia larvae in the above-mentioned bait feeding management refers to the method set for using formalin to prevent fry from getting sick in the juvenile fish stage.

[0072] The concentration of formalin used for the above-mentioned breeding tools before use is shown in Table 2.

[0073] As shown in Table 1, adopting concentration is that the formalin solution of 80-130mg / L carries out the above medicated bath of 6h to sick fry, adopting concentration is that the formalin solution of 200mg / L carries out the above medicated bath of 4h to sick fry, or adopting concentration greater than the formalin solution of 300mg / L carries out the above medicated bath of 2h to sick fry, all can make sick fish body surface starch egg dinoflagellate 100% come off.In production, in order to save water, dosage, guarantee production safety, and give full play to the volatilization of formaldehyde in the formalin solution, culture tool is carried out to process without dead angle pathogen killing, the processing method of culture tool has adopted formalin liquid surface spraying method among the present invention, and uses plastic film to cover and spend the night.Again follow the principle that disease prevention is more important than disease treatment, strengthen the processing of culture tool, in conjunction with actual experience effect, the research and development personnel selects the formalin that concentration is 300mg / L to process production tool, and coordinates other medicines, operating method, accomplishes to be foolproof.

[0074] 2. The concentration and time set for the above-mentioned formalin treatment of fertilized eggs are based on the following experimental results and reference to the experimental results of formalin treatment of diseased fry:

[0075] Experimental Materials

[0076] The experimental materials are clownfish fertilized eggs that are about to break the membrane. The main characteristics are: they aggregate and adhere to the tiles (attachment base).

[0077] Experimental methods

[0078] The fertilized eggs of clownfish were bathed in formalin solution of different concentrations, and the hatching rate and deformity rate were measured after a predetermined period of time. Five experimental groups were set up, and each experimental group used 500-2000 fertilized eggs for bathing. The hatching rate and deformity rate were calculated as follows: hatching rate = number of hatched fry / number of fertilized eggs × 100%; deformity rate = number of deformed eggs / number of hatched fry × 100%.

[0079] Experimental results

[0080] Table 3 Effects of different formalin bath concentrations on the hatching rate and deformity rate of clownfish fertilized eggs

[0081]

[0082] As shown in Table 3, the experimental results show that the deformity rate of hatched fry is lower and the hatching rate is higher after the fertilized eggs are soaked in 200 mg / L formalin. Because it is difficult to detect starch egg dinoflagellate from the surface of the fertilized eggs, this experiment comprehensively considers the effect of 200 mg / L formalin on the shedding of starch egg dinoflagellate when the diseased fry are soaked in Table 1. Therefore, in step (2), 200 mg / L formalin is used to treat the fertilized eggs for 10 minutes.

[0083] The concentration and method of use of formalin for preventing disease in fry are based on the safe concentration of formalin solution for soaking clownfish fry. The relevant experiments are described as follows:

[0084] Experimental Materials

[0085] Clownfish larvae on day 6 after rupture of the membrane.

[0086] Experimental methods

[0087] The experiment adopted the still water method biological test (Wu Bangcan et al., 1998). During the experiment, the liquid was replaced every 24 hours to maintain the original liquid concentration, and the air was continuously inflated in an appropriate amount. The equal logarithmic interval method (Zheng Weiyun et al., 1993) was used to set the concentration group. This experiment set up 7 concentration groups and 1 control group, and each group had 3 parallel experiments. 30 experimental fish were put into each group, and their behavior, poisoning symptoms, and death effects were observed in the test liquid. After poisoning, if there was no response to multiple stimulations within 5 minutes, it could be judged as death. The fish were immediately fished out and the time of death was recorded. The survival status of each group of experimental fish was recorded for 24 hours and 48 hours, the average number of deaths was calculated, converted into probability units, and the median lethal concentration (LC50) was calculated using linear interpolation. 50 ). The formula for calculating safe concentration is: safe concentration (SC) = 48hLC 50 ×0.3 / (24hLC 50 / 48hLC 50 ) 3 (Zhou Yongxin et al., 1989)

[0088] Experimental results

[0089] The results are shown in Table 4. The half-lethal concentration (24hLC) of the experimental fish 50 66.20 mg / L, 48hLC 50 It is 62.47 mg / L.

[0090] According to the formula, SC is calculated to be 15.75 mg / L.

[0091] Based on the above experimental results, the safe concentration of formalin used in steps (3) and (4) to prevent clownfish from being infected with diseases such as amylodinium ovale is 15.75 mg / L, with reference to the safe concentration of formalin used to soak clownfish larvae. After long-term and repeated observations, the larval stage of clownfish seedlings was able to achieve a survival rate of 70%-80% under these experimental conditions. It is speculated that maintaining the formalin concentration in the nursery water at above 15.75 mg / L under these experimental conditions can inhibit the reproduction, attachment, and spread of amylodinium ovale to a certain extent.

[0092] Table 4 Results of formalin toxicity test on clownfish larvae

[0093]

[0094] The method of the present invention has the advantages of low cost and simple operation. The single use of formalin treatment can not only achieve a relatively ideal prevention effect of amyloidosis, but also reduce the infection of other parasites and fungi on the fish body. The flow-through culture mode is adopted in the later stage of juvenile fish cultivation, which ensures the clean living environment of the clownfish, plays an important role in preventing the clownfish from being infected with diseases such as amyloidosis, and effectively improves the survival rate of the clownfish.

[0095] In order to verify that the breeding method of the present invention can indeed improve the survival rate of clownfish, the following examples are given:

[0096] From June to November 2022, clownfish breeding was carried out at a farm in Hangu District, Tianjin. A total of 20 pairs of broodstock spawned at the farm. Sixty 30L glass aquariums were used for initial seed cultivation, based on the development of different batches of fertilized eggs. The aquariums were numbered 1, 2, 3, 4, 5, 6, and so on. Tanks 1, 11, and 21 served as controls and were cultured using conventional methods. The remaining aquariums employed the following methods to effectively prevent and control diseases such as clownfish starch ova and dinoflagellates:

[0097] (1) Management of aquaculture water and equipment, including the preparation of aquaculture water and the handling of aquaculture equipment;

[0098] The aquaculture water is prepared by filtering and removing impurities, sterilizing with ultraviolet light, softening with ion exchange, and then adding imported sea crystals.

[0099] The treatment of the breeding tools is mainly to brush the tank, air pipe, air stone and sewage suction tool used in the breeding plan, and then use 300g / m 3 Spray the surface evenly with formalin solution to kill pathogens, then cover with plastic film overnight. Rinse with aquaculture water three times the next day, drain and set aside. Repeat the above operation after each use of aquaculture tools to prepare for subsequent aquaculture use.

[0100] (2) Fertilized egg incubation: Before transferring the fertilized eggs and their attachment substrate to the tank, soak them in formalin at a dosage of 200 mg / L for 10 minutes. During this period, aeration is used to maintain the dissolved oxygen content of the water at 5-6 mg / L. At the same time, the aeration bubbles are required to cause the fertilized eggs to sway slightly. Before transferring the fertilized eggs, add fresh water to the tank in advance that just covers the attachment substrate of the fertilized eggs, and place aeration stones. Finally, transfer the treated attachment substrate with the fertilized eggs to the prepared tank for incubation in the dark.

[0101] (3) Larval cultivation and management, including water change management, feed feeding management, drug prevention, aeration management, daily management and inspection;

[0102] Among them, water change management: 24 hours after the fry rupture, add 1 times the volume of new water. This new water is obtained by filtering the breeding water with filter cotton, removing dirt with a protein skimmer, sterilizing with ultraviolet light, aerating with an air pump, and adjusting the temperature with air conditioning. Subsequently, during the breeding process, the water is changed every 24 hours, and the water change operation uses a dedicated and special sewage suction device to drain 1 / 2 of the volume of old water in the breeding tank by siphoning, and add an equal amount of new water at the same temperature.

[0103] The bait feeding management includes feeding newly hatched fry with SS-type rotifers in combination with marine chlorella. The rotifers are treated with 80 mg / L formalin and 5 mg / L oxytetracycline for 4-8 hours and filtered through 400-mesh special gauze to remove impurities and liquid medicine before use. This is to remove or kill starch dinoflagellates and other pathogens that may be carried in the bait.

[0104] Drug prevention: According to the actual volume of water in the tank, add formalin to make the final concentration of the drug solution 15.75g / m 3 The amount of formalin added after the water change operation is calculated as follows: water change volume × 15.75 g / m 3 calculate;

[0105] Aeration management: Maintain the dissolved oxygen level in the aquaculture water at around 5.5 mg / L. The aeration intensity should be such that the fry do not experience severe up and down shocks.

[0106] (4) Cultivation and management of juvenile fish

[0107] The juvenile stage cultivation management includes water change management, bait feeding management, drug prevention, aeration management, daily management and inspection; wherein the drug prevention is the same as the larval stage management;

[0108] The water change management: water change operation is carried out every 24 hours when the juvenile fish enter the stage, that is, a special and dedicated sewage suction device is used to discharge 1 / 2 volume of old water in the breeding tank by siphon principle, and an equal amount of new water of the same temperature is added;

[0109] Feed management: Use newly hatched Artemia eggs for feeding. The Artemia larvae must be treated with 80mg / L formalin and 5mg / L oxytetracycline for 4-8 hours and filtered through 150-200 mesh special gauze to remove impurities and liquid medicine before use. The purpose is to eliminate or kill starch egg dinoflagellates and other pathogens that may be carried in the bait;

[0110] Aeration management: Maintain the dissolved oxygen level in the aquaculture water at around 6 mg / L. The aeration intensity should be such that the fry do not experience severe up and down shocks.

[0111] (5) Cultivation and management of juvenile fish

[0112] Juvenile fish cultivation and management include water flow management, feeding management, drug prevention, daily management, and inspections. Regarding water flow management, fertilized eggs spend about four weeks in the tank after rupture. When the fry have an average body length of more than 0.8-1.0 cm, are strong, and have further improved their swimming ability, they can be moved into circulating water tanks for cultivation. The initial water flow rate is adjusted to 5 L / min. As the juvenile fish's adaptability improves, the flow rate can be appropriately increased, generally not exceeding 10 L / min.

[0113] Feeding management: gradually acclimate the seedlings to artificial compound feed, feeding them twice a day in the morning and evening;

[0114] Drug prevention: The seedlings are bathed in formalin in the circulating water system of the circulating water tank every two weeks and the water is replaced with new water. The specific method is as follows: according to the actual volume of water in the circulating water aquaculture system, formalin is added to make the final concentration of the solution 80g / m 3 After 4-6 hours of circulating immersion, drain about 4 / 5 of the volume of old water and add appropriate new water; during the bathing period, the dissolved oxygen is maintained above 5.5 mg / L.

[0115] The above-mentioned larval stage cultivation management and juvenile stage cultivation management, as well as the daily management and inspection in the juvenile stage cultivation management are the same, and the specific contents are as follows:

[0116] Daily management: Clean the bottom and walls of the tank at a fixed time every morning, using a dedicated and special sewage suction device to absorb the dirt on the entire tank wall using the siphon principle;

[0117] Inspection: Use a bright yellow flashlight with good reflectivity to carefully observe the surface of the fry for white spots three times a day, morning, noon and evening, to promptly identify fry with darker body color and abnormal behavior, and perform microscopic examination on their gills, epidermis and other tissues to determine the occurrence of starch egg dinoflagellate disease; isolate symptomatic individuals in a timely manner and provide individual treatment.

[0118] Regarding feeding management, clownfish larvae should preferably be fed SS-type rotifers. Five to eight days after hatching, rotifers can be mixed with Artemia larvae. After three days of transition, Artemia larvae can be fed alone, gradually increasing the amount of Artemia larvae. Both rotifers and Artemia larvae should be treated with a combination of 80 mg / L formalin and 5 mg / L oxytetracycline for 4-8 hours to kill any bacteria, fungi, and parasites that may be present on their bodies or in the water. All biological baits should be filtered through a special gauze filter before feeding to remove impurities and any liquid medicine.

[0119] Statistics from the three control tanks, No. 1, 11, and 21, showed an average survival rate of 75% three days after hatching, 60% seven days after hatching, and 12% 14 days after hatching. Because the farm had a history of amylodinium outbreak, most of the experimental fry batches, which had not taken preventive measures, died within two weeks of hatching due to the outbreak, though the specific timing varied. However, the fry in the experimental tanks using the method of the present invention had an average survival rate of 80% three days after hatching, 75% seven days after hatching, 70% 14 days after hatching, and 80% 28 days after hatching, representing significantly higher survival rates than the control group.

[0120] The present invention respectively takes into account aspects such as fertilized egg hatching, larval stage cultivation and management, and juvenile stage cultivation and management, as well as water change management, drug prevention, bait feeding management, and aeration management in the juvenile stage cultivation and management. By adjusting the aquaculture environment including sewage suction, water change, and aeration, using drugs such as potassium permanganate and formalin, and scientifically processing and replacing bait, the present invention effectively prevents the outbreak of amyloidosis during the aquaculture process, reduces the reproduction and spread of other parasites and fungi, effectively improves the survival rate of clownfish seedlings, and lays a foundation for the large-scale development of the clownfish industry.

[0121] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0122] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for improving the survival rate of clownfish seedlings, characterized in that: It includes the management of aquaculture water and equipment, hatching of fertilized eggs, cultivation and management of larvae, cultivation and management of juveniles, and cultivation and management of juveniles. The specific operations include the following: (1) Management of aquaculture water and equipment, including preparation of aquaculture water and handling of aquaculture equipment; (2) Fertilized egg incubation: Use a formalin solution with a concentration of 200 mg / L to soak the fertilized eggs and the attachment substrate for 10 minutes. During this period, aeration is used to maintain the dissolved oxygen content of the water at 5-6 mg / L. Add enough aquaculture water to the tank to just soak the fertilized egg attachment substrate, and place aeration stones. Transfer the treated attachment substrate with the fertilized eggs to the prepared tank for incubation in the dark. (3) Frying management, including water change management, feed management, drug prevention and aeration management; water change management: 24 hours after the fry rupture, add new water to fill the tank; then during the culture process, change the water every 24 hours, and the single water change volume is 1 / 2 of the tank water capacity; feed management: newly hatched fry are fed with ss-type rotifers combined with seawater chlorella, and the fed rotifers must be treated with 80 mg / L formalin and 5 mg / L oxytetracycline for 4-8 hours and filtered through 400 mesh special gauze; drug prevention: according to the actual volume of water in the tank, add formalin to make the final concentration of the drug solution 15.75 g / m 3 The amount of formalin added after the water change operation is calculated as follows: water volume × 15.75 g / m 3 Calculation; Aeration management: maintain dissolved oxygen in aquaculture water at 5.5 mg / L; (4) Cultivation and management of juvenile fish, including water change management, feed feeding management, drug prevention and aeration management; wherein the drug prevention method is the same as that in the larval stage; the water change management: water is changed every 24 hours during the juvenile stage, and the single water change volume is 1 / 2 of the water capacity of the tank; feed feeding management: newly hatched Artemia eggs are used for feeding, and the Artemia larvae fed must be treated with 80 mg / L formalin and 5 mg / L oxytetracycline for 4-8 hours and filtered through 150-200 mesh special gauze; aeration management: the dissolved oxygen in the aquaculture water is maintained at 6 mg / L; (5) Cultivation and management of juvenile fish, including water flow management, feed management and drug prevention; water flow management: after the fertilized eggs break the membrane, they spend 4 weeks in the tank. When the average body length of the fry is greater than 0.8 cm, they are moved into the circulating water system for breeding. The initial water flow rate is adjusted to 5L / min. As the adaptability of the fry increases, the flow rate is appropriately increased, but it needs to be gradually increased and not more than 10L / min; feed management: the fry are gradually acclimated to eat artificial compound feed, and are fed twice a day in the morning and evening; drug prevention: the fry and the circulating water system are bathed in formalin once every two weeks. Specifically, formalin is added according to the actual volume of the water in the circulating water system to make the final concentration of the drug solution 80 g / m 3 After 4-6 hours of circulating immersion, drain 4 / 5 of the old water in the tank and add appropriate new water; the dissolved oxygen during the immersion period is maintained above 5.5 mg / L; The larval stage cultivation management and the juvenile stage cultivation management and the juvenile stage cultivation management both include daily management and inspections. The specific contents are as follows: Daily management: Clean the bottom and walls of the tank at a fixed time every morning, using a sewage suction device to absorb the dirt on the entire tank wall using the siphon principle; Inspection: Use a bright yellow flashlight with good reflectivity to carefully observe the surface of the fry for white spots three times a day, morning, noon and evening. Detect fry with darker body color or abnormal behavior in time, and perform microscopic examination of their gills and epidermal tissue to determine the occurrence of the dinoflagellate disease. Isolate the symptomatic individuals in time and provide individual treatment. The tank is a small indoor hatching and breeding device for clownfish, and its outer surface is covered with opaque wallpaper; The aquaculture water is tap water, which is filtered to remove impurities, sterilized by ultraviolet light, softened by ion exchange, and then added with imported sea crystals; Treatment of the breeding tools: First, scrub the tank, air pipe, air stone, and suction tool used in the breeding plan, and then use a concentration of 30 g / m 3 Spray the surface of the equipment with potassium permanganate solution evenly for routine disinfection, and leave it overnight. Rinse it three times with aquaculture water the next day, then drain and set aside. Repeat the above operation process after each use of the aquaculture equipment to prepare for subsequent aquaculture. If the aquaculture equipment is used in an aquaculture environment where amylodinium disease has recently broken out, it is necessary to use a solution of 300 g / m3 of potassium permanganate solution after brushing. 3 Spray the surface of the equipment with formalin solution and cover it with plastic film overnight for 6-12 hours, then use the above operation process for treatment.

2. the cultivation method that improves clownfish seedling survival rate according to claim 1, is characterized in that: The new water is aquaculture water and is obtained after passing through filter cotton, protein separator, ultraviolet sterilization, aeration and temperature adjustment in sequence.

3. the cultivation method that improves clownfish seedling survival rate according to claim 1, is characterized in that: The water replacement operation adopts a sewage suction device to discharge 1 / 2 volume of old water in the tank by siphon principle, and add an equal amount of new water at the same temperature.

4. the cultivation method that improves the survival rate of clownfish seedlings according to claim 3, is characterized in that: When adding an equal amount of new water of the same temperature during the water change process, the operation must be gentle, without causing too much impact on the fry, and without stirring the bottom of the tank. The container filled with water is completely immersed in the tank. When the water surfaces inside and outside the container are on the same plane, the container is rotated, the container mouth is tilted downward, and then gently pulled out of the tank. The sewage suction device used in the water change process must have the function of adjusting the water flow size to prevent the fry from being accidentally sucked in. The sewage suction operation needs to be gentle and the bottom of the tank should not be excessively stirred.

5. the breeding method that improves the survival rate of clownfish seedlings according to claim 1, is characterized in that: The time period for cleaning the bottom and wall of the tank in the daily management is after feeding.

6. The method for cultivating anemonefish seedlings according to claim 1, wherein: The tool for spraying in the treatment of the breeding tools is a spraying pot; the specific operation is to put all the breeding tools into the tank and spray the medicine.

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