1080 results about "Freshwater fish" patented technology

The invention discloses a biogas slurry ecological purification method based on microalgae cultivation. The method comprises the following steps: (1) biogas slurry pretreatment; (2) habituated culture of autotrophic microalgae, namely, obtaining algae strains capable of rapidly growing in 70%-100% biogas slurry; (3) preparation of a seed solution; (4) a biogas slurry purification method during growing of microalgae, namely, after expanded cultivation, inoculating the habituated algae species into an open photobioreactor for cultivation, obtaining chlorella biomass growing by high density through a semi-continuous culture method and optimized methods such as fed-batch cultivation, and purifying the biogas slurry; (5) biochemical breaking of microalgae cell walls, namely, introducing the microalgae cells into a biochemical wall breaking pool, putting freshwater fish into the pool, and obtaining algae slurry subjected to wall breaking; and (6) collection of the microalgae cells and recycling of the biogas slurry. According to the method, not only is a method provided for purifying the biogas slurry, but also the obtained algae cells and the biogas slurry can be recycled, so that ecologicalization treatment of the biogas slurry is realized, the environment is improved, and furthermore, the economic and social benefits are produced.

The invention relates to a general-purpose composite Chinese herbal medicine immune enhancer for freshwater cultured fish, which is made of raw materials with the following weight ratios, based on the amount added per ton of feed: rhubarb 800-2000g; Sanqi 350-1000g; water Silybum 1200-2500g; Cassia 600-800g; Astragalus 600-2000g; Scutellaria baicalensis 500-900g; 500-1500g; Garlic 1000-2000g. After many tests in the laboratory, it has been proved that the general-purpose compound Chinese herbal medicine immune enhancer for freshwater aquaculture fish can improve the survival rate of a variety of freshwater aquaculture fish in the process of attacking viruses; The long-term breeding experiment of farmed fish feed proves that the general-purpose compound Chinese herbal medicine immune enhancer for freshwater farmed fish can effectively reduce the incidence of a variety of high-density farmed freshwater fish and improve the survival of the breed; the additive is safe, efficient, and has no side effects for long-term use. The breeding objects have strong vitality, rapid growth, bright body color, high feed conversion rate, and good breeding benefits.

The invention discloses freshwater fish feed and a preparation method thereof. The feed comprises the following materials in percentage by weight: 5%-17% of import fish powder, 8%-22% of flour, 3%-16% of potato starch, 3%-18% of beer yeast, 5%-15% of bean pulps, 5%-15% of peanut pulps, 5%-10% of rape seed cakes, 2%-8% of corn powder, 3%-9% of cooked egg protein, 5%-8% of dried meat floss powder, 1%-2% of liquid phytase, 1%-3% of non-starch polysaccharase, 0.5%-1.9% of glutamine, 1%-2% of microecological preparation and 1%-3% of immune polysaccharides. The preparation process comprises a crushing step, a mixing step, a pelletizing step and a spraying step. The freshwater fish feed has the beneficial effects of being capable of well satisfying the nutrition needs of freshwater fish, improving the immunity of the freshwater fish, prompting intestinal absorption and improving the production performance of the freshwater fish.

The invention discloses fish feed for mixed culture and a preparation method of the fish feed. The feed comprises one or more of the following ingredients: soya bean meal, rapeseed cakes, rice bran meal, salt, liquid vitamin C, betaine and traditional Chinese medicine additives, and the preparation method comprises the steps of smashing, blending and pelletizing. The fish feed and the preparationmethod have the benefits that on the premise that the yield of grass carps is slightly increased, the yields of breams, crucian carps, variegated carps and silver carps are significantly increased; the utilization efficiency of the feed is effectively improved; the cost of the feed is saved; and the economic benefits of feeding freshwater fish are improved.

The invention relates to a mixed feed for mixed aquaculture of freshwater fishes. The mixed feed includes a basic material. The basic material includes fish meal, soybean meal, wheat, cottonseed meal, rapeseed meal and soybean oil, and also includes by weight: 1.5-2.2% of calcium phosphate, 1.5-2.2% of bentonite, 1.5-2.2% of zeolite powder, 0.1-0.25% of choline chloride, 0.1-0.25% of salt, 0.02-0.05% of compound probiotics, 0.04-0.08% of vitamin C, 0.005-0.02% of allicin, 1.0-2.0% of compound vitamins and 1.0-2.5% of compound mineral salts. The feed is suitable for intensive culture or polyculture of megalobrama amblycephala, black carp, grass carp, common carp and the like, so that the freshwater fish feed is generalized, the return rate of the feed is improved, the aquaculture water eutrophication and fish liver and gallbladder diseases are reduced, the output of unit aquatic products is raised, and the economic benefits of farmers are significantly improved.

The invention discloses a method for making fermented surimi by utilizing a lactic acid bacteria starter, and the method is characterized by adopting fresh or frozen fish as the raw material and comprising the steps of preprocessing, chopping, inoculating the starter, filling, fermenting and storing, thus obtaining the surimi. The product processed in the method has fresh taste, good gel property, intense fermentation flavor, high nutritive value and good safety and can solve the problems that protein of freshwater fish is easy to modify when being frozen and has poor gel strength and heavy fishy smell, and the method has simple process, greatly enhances the yield rate and the gel strength of the product and improves the flavor of surimi products.

This invention discloses a method for preparing freshwater fish skin collagen. The method comprises: (1) washing fish skin, draining, cutting, and soaking in 0.001-0.2 M alkali solution containing 0.005-2% (v / v) H2O2 for 3-48 h; (2) stirring at a high speed, washing and soaking with an organic reagent; (3) extracting with acid solution (pH = 1.0-5.0) containing 0.01-2% (m / v) pepsin for 12-64 h, and filtering with 30-100 mu.m membrane, and then with 1-30 mu.m membrane; (4) adding 5 M NaCl solution into the filtrate to 0.8-2.0 M, centrifuging, dissolving the precipitate in 0.001-0.1 M acetic acid, dialyzing with distilled water, and freeze-drying to obtain white and odorless collagen solid. The collagen can be widely used in food, cosmetic and biomedical fields.

The invention relates to a method for preparing compound amino acid chelate calcium from low-value freshwater fish bones. The method comprises the following steps: washing and steaming fish bones andthen soaking the fish bones in sodium hydroxide; then washing the fish bones to be neutral; drying and pulverizing the fish bones; extracting calcium in fish bone powder by an acidolysis method; chelating calcium ions in the fish bone powder by using compound amino acid; carrying out centrifugation to obtain clear liquid; washing an obtained product twice by absolute alcohol and then carrying outcentrifugation to obtain precipitates; and drying and pulverizing the precipitates to obtain a calcium acid chelate capsule product. The invention firstly adopts the fish bones which are by-products of processing low-value freshwater fishes to prepare the compound amino acid chelate calcium, thereby greatly improving the additional value of the by-products of the freshwater fishes. Proved by an animal experiment, the compound amino acid chelate calcium has thighbones calcium content of a rat of 32.81-43.41 and thighbones calcium retention rate of 5.30-16.30. If the compound amino acid chelatecalcium is matched with VD3, the bioavailability can be increased more and the effect of calcium supplement is improved. The calcium supplement effect of the compound amino acid chelate calcium is equivalent to the calcium supplement effect of calcium gluconate and higher than the calcium supplement effect of calcium carbonate, but the calcium retention rate of the compound amino acid chelate calcium is obviously higher than that of the calcium gluconate group and the calcium carbonate group.

The invention is concerned with the freshwater dried fish products and preparation method, the compounding is: freshwater grass crap, salt, sugar, flavor essence, rice wine, ginger juice, water. The invention is good for disease of liver, kidney, brain, heart, which is without side effect.

The invention discloses a method for producing vacuum-seasoned drunk dried fish, belonging to the field of food processing technology. The method comprises the following steps: killing freshwater fish serving as a raw material; cleaning blood; curing to remove fishy smell, cleaning fish halogen, draining water, vacuum seasoning, air drying, dividing and trimming, filling the dried fish and seasoning in a boiling bag; vacuumizing and packing; sterilizing at a high temperature and cleaning the packing bag; externally packing and storing the product. Compared with the traditional process, the method disclosed by the invention increases a step of vacuum seasoning, thus the dried fish is more delicate and tasty and has richer flavor.

The invention relates to a method and a device for fish flesh detection. The method comprises the following steps of 1, acquiring a hyperspectral image of a fish flesh sample, wherein the hyperspectral image comprises spectral data of multiple wavebands, 2, extracting the spectral data of N feature wavebands, wherein N is greater than 1, and 3, utilizing the extracted spectral data of the N feature wavebands as an input value of a learning vector quantization model, and identifying if the fish flesh sample belongs to marine fishes or freshwater fishes according to an output value of the learning vector quantization model. The method and the device can realize fast and accurate identification of marine fishes or freshwater fishes and can realize fast and accurate detection of mercury content of fish flesh.

The invention belongs to the agricultural natural product extraction field, in particular relating to a method for extracting unmodified collagen from freshwater fish scale. The method comprises the following steps that: (1) cleaned scale is added in distilled water and is stirred intermittently by a motor stirrer for 3 to 5 minutes till the surface of the scale has no attachment of pigment and fat, etc.; the scale is crushed to 40 to 50 meshes after natural air drying and low-temperature drying; (2) the materials of the step (1) are added into 8 to 10 percent of citric acid and malic acid solution according to a ratio of between 1 to 10 and 1 to 20 so as to carry out ice-water bath microwave treatment for 2 minutes and decalcification at a temperature of between 10 and 20 DEG C for 8 to 24 hours; then, the solution is filtered and the filtrate undergoes standing at a temperature lower than 10 DEG C for 5 to 10 hours so as to obtain calcium citrate precipitate; (3) according to a ratio of between 1 to 5 and 1 to 20, 1 percent malic acid or citric acid solution (containing protease) is added into the de-calcification scale obtained after the treatment of step (2), and is stirred and extracted 2 to 4 times at a temperature of between 0 and 20 DEG C with each time lasting 12 to 48 hours; then, centrifugation is carried out, and supernatant is taken out; NaCl is added till final concentration reach 0.7 to 0.90 mol / L, and then salting out is carried out over night; centrifugation and deposition are carried out, and the obtained substance is dissolved in 0.50mol / L acetic acid; then, salting out and dissolving operations are repeated one more time, and the precipitate undergoes dialysis so as to obtain the product of the invention through freeze drying.

The invention relates to a transport method for freshwater fish kept alive without water, in particular to a transport method for the freshwater fish kept alive without water at ice temperature. The transport method comprises the following steps of: fostering the freshwater fish and carrying out temperature reduction and dormancy on the freshwater fish; transferring the freshwater fish into an inflating bag, oxygenating and sealing; and transporting the inflating bag to a destination and wakening the freshwater fish. The transport method is characterized in that the temperature reduction and dormancy means that gradient temperature reduction is carried out on the freshwater fish to ice temperature; and the wakening for the freshwater fish means that the freshwater fish is wakened by gradient temperature reduction. The invention has the advantages that no chemical agent is used, so that the freshwater has no side effect on a human body, potential safety hazards are reduced and the nutrient value of the freshwater is saved to the maximum extent; the cost is low; and the survival time of the freshwater fish can reach 6-81h and the survival rate of the freshwater fish reaches over 95 percent. The transport method disclosed by the invention is simple and easy for operation, has high automatic degree and can be used for realizing large-batch transportation.

The invention discloses a preparation method of an instant leisure flavored fermented fish product. According to the invention, living carp is used as a raw material to be prepared into the instant leisure fermented fish product with unique flavor through the steps of pretreatment, cutting into blocks, curing, drying, preparing a leavening agent, blending, sealing and fermenting. The method is combined with low-salt curing technology, microorganism mixed inoculation technology and temperature controlled fermentation technology on the basis of conventional fermented sour fish, so that the quality and safety of the sour fish can be improved, the storage period can be prolonged, the production cycle can be effectively shortened, the production efficiency can be increased, standardized and large-scale production can be facilitated, the earthy smell of freshwater fish can be removed, ester can be produced to enhance aroma, and the mature flavor and taste of the fish product can be increased. The fish product produced by adopting the method is soft and high in resilience of the meat, bright in color and thick in acid taste, can be eaten after being unsealed, and can be developed into an instant leisure flavored product.

The invention particularly relates to a low-temperature keep-alive transporter for freshwater fishes. The low-temperature keep-alive transporter for freshwater fishes comprises a PLC (programmable logic controller) control system (100), an aeration system (200), a fish box (300), a water circulation system (400), a filter system (430) and a water heating-cooling unit (500). The low-temperature keep-alive transporter for freshwater fishes is capable of automatically monitoring pH, dissolved oxygen and temperature of the water in the live fish transport box and storing and recording the data in the transport process, such as the pH, the dissolved oxygen and the temperature. The low-temperature keep-alive transporter for freshwater fishes is simple and convenient to operate. An operator can click on a touch screen to achieve the whole control process. The low-temperature keep-alive transporter for freshwater fishes can be used for low-temperature keep-alive transport and controlled freezing-point transport. No water needs to be added during the whole transport process. The biological water standard required by the high-density transport of live aquatic products can be guaranteed by the aid of the water circulation and the filter system of the transporter.

The invention discloses an environmentally-friendly pond culture method for freshwater shrimps. The method comprises the following steps of: (1) selection of a pond; (2) pond reformation, (3) stocking of shrimp seedlings, (4) fodder and feeding, (5) water quality control and daily management and (6) catch of adult shrimps. Compared with the prior art, the method has the advantages that: popularization and application of the environmentally-friendly pond culture method for the freshwater shrimps successfully researched by the invention can gain better economic benefit in freshwater shrimp culture, more important, the water quality of the pond of the culture mode is kept well all the time, nearly no culture wastewater is drained and the ecological benefit is extremely obvious. Under the conditions of frequent disease attack of the current other shrimp varieties and higher culture risk, the popularization of the environmentally-friendly culture mode for the freshwater shrimps is a good path for becoming rich for fishermen.

The invention discloses a fermented low-salt semi-dried tilapia mossambica, a processing method thereof and application thereof. The processing method comprises the steps of: removing the internal organs and the scales of the tilapia mossambica; cutting along backside or abdomen; overturning; flatly pressing to form a symmetrical tilapia mossambica piece except the tail of the tilapia mossambica;washing with cleaning water; washing with salt water with 1%-4% of concentration to remove fishy smell and obtain the tilapia mossambica piece without the fishy smell; paving salt on the surface of the tilapia mossambica piece without the fishy smell, wherein the weight of the salt is equal to 3-8% of that of the tilapia mossambica; sousing for 8-24 hours; drying; or soaking for 8-24 hours with 5-10% of salt water to obtain the low-salt tilapia mossambica piece; spraying zymophyte on the surface of the tilapia mossambica piece, wherein the inoculum size of the zymophyte is 105-107 CFU / g fish meat; fermenting for 10-48 hours in a sealing way under the temperature of 12-20 DEG C; and drying the fermented tilapia mossambica piece to obtain the fermented low-salt semi-dried tilapia mossambicawith 30-60% of water content. The product has lubricating meat quality and typical flavor of dried meat. The processing method can be adapted to processing freshwater fishes.

The invention relates to a method for improving quality of frozen freshwater fish surimi. The method comprises the following steps: pretreating a raw material fish, and collecting meat; alternatively bleaching the meat with a sodium carbonate solution and clean water; adding 2.5% of a low sodium salt mixture for blending; adding the following components in percentage by weight in chopping and stirring processes: 60-70% of fish meat, 10-15% of starch, 5-8% of a fishbone enzymatic product, 0.4-0.7% of a composite antifreeze agent, 0.08-0.12% of a composite antibacterial agent, 0.02-0.04% of tea polyphenol, 0.01-0.012% of TBHQ, 0.015-0.02% of L-sodium ascorbate and 10-18% of icy water; subsequently forming; and freezing, thereby obtaining a frozen fish surimi product with improved quality. By adopting the method, not only are the water retention property, oxidation resistance and antibacterial activity of the fish surimi in the machining process improved, but also the nutrient value of the fish surimi can be increased, so that the fish surimi product can be relatively applicable to industrial production and preservation.

The invention discloses a skin roll for pets and a preparation method thereof. The skin roll for the pets comprises the following preparation raw materials: line fish flesh, starch, vegetable protein, animal fat, edible gum, a water-retaining agent, a preservative and / or an antioxidant. The line fish flesh is one or several of cod flesh, Spanish mackerel flesh, black sea bream flesh and freshwater fish flesh. The starch is one or several of potato starch, cassava starch, corn modified starch, pre-gelatinized starch, waxy corn starch, corn starch, potato modified starch, cassava modified starch, sweet potato starch and wheat starch. The skin roll has intense fragrance per se, can attract dogs and reinforces the interest and the appetite of the dogs to the product, and the dogs can not be sick of the product after the dogs eat the product for a long time. Meanwhile, fishy skin can replenish nutrient components required by the dogs and finally can be digested very well.

The invention discloses a method for preparing fish-and-rice mixed breaded fish sticks by using a microorganism leavening agent. The method is characterized in that fresh fish or frozen fish is taken as a raw material; and the fish-and-rice mixed breaded fish sticks are prepared by the following steps: pretreating and mashing the fresh fish or the frozen fish; inoculating the leavening agent; and filling, fermenting, sterilizing, cooling and storing. To sum up, the fish-and-rice mixed breaded fish sticks prepared by the method disclosed by the invention have unique fermentation flavors, are soft, fine and smooth in texture, and have the advantages of high resilience, high nutritive value, good safety and long storage period, thereby especially providing a brand new processing way for processing freshwater fish in China.

The invention relates to a high-calcium freshwater fish ball and a preparation method of the high-calcium freshwater fish ball, belonging to the technical field of the processing and the producing of food. The minced fillet and the fishbone mud are taken as raw materials. The preparation method comprises the following steps of: adding shop fat with a certain quantity and the other auxiliary materials, chopping in a mixing way, forming fish ball, curing fish ball and the like. On the basis that the peculiar taste of the fish ball is guaranteed, the high-calcium freshwater fish ball provided by the invention is rich in elasticity, and has the loose, soft, fine and smooth mouth feel when being eaten, and the pursuing of modern people to nutrition health can be met. The problems that the calcium is sufficiently ingested by people, and the problem that the fish bone generated when the freshwater is deeply processed is not well used in the prior art can be solved, the additional value of the fish bone can be improved, a feasible technical scheme can be provided for the treatment of the fish bone, and the considerable economic benefit can be brought to the enterprises.

The invention discloses an antibiotic free, hormone free and harmful additive free biological mixed feed capable of improving quality of meat and suitable for feeding of various meat animals, and a production method thereof. The biological mixed feed comprises the following materials, by weight: 8-10% of biological fermentation cotton seed meal, 3-5% of polypeptide biological blood powder, 80-84% of mixed forage powder, 3-5% of feed additive and 1-5% of plant oil. According to exogenous enzyme and microbial fermentation, macro-molecule protein raw materials are decomposed into polypeptides and small peptides, so as to degrade anti-nutritional factors like non-starch polysaccharides in the forage and increase utilization rate of the forage; meanwhile, abundant B-group vitamin, free amino acid and organic acidity are generated during a fermentation process to promote deposition of flavor amino acid, inosinic acid and unsaturated fatty acid in muscle, so as to enhance quality of meat. Freshwater fish, fryers and growing and fattening pigs fed by the biological mixed feed for animals of the invention have characteristics of fast growth speed, and elastic, chewy, delicious and strongly fragrant fish meat, chicken and pork. The method of the invention is simple, requires no special equipment and is suitable for industrialized production.

The invention relates to a large-scale method for raising seedlings of freshwater shrimps, which mainly comprises the following steps: the mixture ratio of female shrimps to male shrimps is between 3 and 5 to 1, and the shrimps come from different places, are more than 4.5 centimeters, have mature gonad, are able-bodied and scot-free, and have sensitive reaction to external stimulus; or shrimps with eggs and more than 5 centimeters are directly purchased in the mating period, taken as parent strains and placed into a seedling pool; high-quality full-rate mixed feed is thrown and fed from the next day; when zoeas occur in the pool, soybean milk is splashed; when shrimp larvaes begin to be abnormal, powdery mixed feed is fed when the soybean milk is splashed simultaneously; and when the proportion of abnormal seedlings is improved, the proportion of the powdery mixed feed is gradually increased and the powdery mixed feed can be completely thrown and fed after 10 days. Moreover, the transparency of a water body is controlled to between 20 and 30 centimeters; the pH value is between 7.5 and 8.5; and the dissolved oxygen is more than 5 milligrams per liter. The method is a scientific, reasonable, low-investment, high-efficiency and large-scale method for raising the seedlings of the freshwater shrimps, can effectively prevent varieties from degeneration, and is favorable for promoting good freshwater shrimps and improving the economic benefit of cultivation.

The invention discloses a disease-resistant feed additive for freshwater fishes and a preparation method thereof. The disease-resistant feed additive is prepared from the following raw materials by weight percent: 0.3-0.4% of allicin, 0.05-0.15% of vitamin C, 15-20% of salt, 35-45% of zeolite powder, 25-35% of fulvic acid, 7.5-10.5% of a Chinese medicine extract, and 7-13% of probiotics powder, wherein the Chinese medicine extract include 20-40% of a rhubarb extract, 20-40% of a rhizoma coptidis extract, and 20-40% of a radix scutellariae extract. The disease-resistant feed additive disclosed by the invention can effectively overcome the diseases such as gill rot diseases, fin-rot diseases, skin ulcerative diseases, bleeding diseases, red skin diseases and body surface festers of freshwater fishes, and then replace antibiotics.

The invention discloses a method for quickly brewing low-salt flavored fish sauce from freshwater fish leftovers. The method mainly comprises the following steps: unfreezing the freshwater fish leftovers, chopping, performing low-salt autolysis, fermenting, and performing flavor fermentation. The method is easy to operate, the low-value freshwater leftovers are quickly brewed to form the low-salt flavored fish sauce, the difficult problem of difficult processing of the freshwater leftovers is solved, and the economic value of freshwater fishes is improved; the fish sauce produced by adopting the method is good in flavor, color and shape, and the fermentation time of the fish sauce produced by adopting the method is shortened to be 38-40 days from 2-3 years in comparison with that of fish sauce produced by adopting a conventional method is adopted.

The invention provides an ecological cycling freshwater aquaculture method. The method comprises: preparing a culture water source, supplying water to culture ponds, filtering water, and treating sewage. The plurality of culture ponds are arranged from left to right in sequence to form a culture pond group. The culture ponds in the culture pond group are connected in parallel, and form a recirculating aquaculture system with a filter tank, a treating pond, a settling pond, a biological package, an aeration tank, and a sterilization pond. Using the ecological cycling freshwater aquaculture method, water of the whole system forms virtuous cycle, and is suitable for growth of freshwater fishes and shrimps, and zero discharge of aquaculture wastewater is realized, and water resource is saved. The ecological cycling freshwater aquaculture method has obvious ecological environment benefits, and meets the sustainable development strategy of the country.

The invention relates to a production process for preparing biological active small peptide with endogenous enzyme, which is characterized in that low value freshwater fish or aquatic product processing leftover is selected as raw material; the raw material is pulped after being cleaned, and water is added to prepare fish cream; the fish cream is put into a zymohydrolysis device, calcium chloride is added in, and the fish cream is heated to raise and control the temperature to be 53 DEG C to 57 DEG C, the ph value is regulated, zymohydrolysis is conducted, to obtain enzymolysis product; enzyme killing and sterilization are conducted to the enzymolysis product, impurities in enzyme- hydrolyzed solution are filtered, to obtain coarsely filtered enzyme- hydrolyzed solution; the enzyme- hydrolyzed solution is concentrated, to obtain liquid or paste biological active small peptide. The production process pursues the best autologous enzymolysis conditions with the endogenous enzyme system in the mechanism of low value freshwater fish, not only greatly saves the cost, but also simplifies the production process of the biological active small peptide, so that the mass production is easy to be realized.

The invention discloses a mixed composite microbial feed for freshwater fish and a production method thereof, wherein the mixed feed contains no antibiotics, no hormones and no harmful additives. The mixed composite microbial feed for freshwater fish comprises the following components, by weight, 8-10% of biologically fermented cottonseed rapeseed meal, 3-5% of polypeptide biological blood powder, 80-84% of mixed feed powder, 3-5% of a feed additive and 1-5% of plant oil. Macromolecular protein raw materials are decomposed into polypeptides and small peptides through an exogenous enzyme and the microbe fermentation, so antinutritional factors of non-starch polysaccharides and the like in the feed are degraded, and the feed utilization rate is improved; the feed contains no antibiotics, no hormones and no harmful feed additives; and the freshwater fish fed with the feed of the invention has the characteristics of fast growth speed and strong disease resistance. A mixed high protein biological feed for adulthood grass carp, which contains 35% or 32% of crude proteins, can be produced through above technology, the generation of hepatobiliary syndrome and three diseases of the grass carp is effectively reduced, and problems that the adulthood grass carp cannot be fed with the high protein feed and the feed of mix-cultured fish is difficult to select are solved; and the freshwater fish fed with the feed of the invention has the advantages of tough fish flesh and delicious taste. The method of the invention has the advantages of simplicity, no need of special equipment, and suitableness of the industrialized production.