How to Raise Catfish? Master the Breeding Techniques and Precautions
Recently, many farmers who want to join the catfish breeding industry have been asking how to raise catfish well. Generally speaking, catfish spend most of their time living at the bottom of the pond, and the bottom layer is also the area where oxygen debt first appears, so during the breeding process the demand for dissolved oxygen is very high. If dissolved oxygen is insufficient, in mild cases it will affect the digestion and absorption of feed, raise breeding costs, and also bring some hidden damage to the fish's body; in severe cases, it will cause floating head, pond turnover and fish death.
How to Raise Catfish
The fingerling pond area is 3/15 hectare to 5/15 hectare, with a water depth of 1.3 to 1.5 m. One week before stocking the fingerlings, complete the pond clearing and disinfection work. Stocking time is generally from July to August. There are two stocking methods: monoculture and polyculture with silver carp and bighead carp fingerlings, with polyculture being better, in which silver carp and bighead carp can play a role in controlling water quality. The stocking density should be determined according to the expected harvest size and pond conditions. Generally, 5000 to 7000 summer fry are stocked per 1/15 hectare, together with 500 to 1000 summer fry of silver carp and bighead carp of similar size. During the fingerling rearing period, artificial feed is mainly used, and the crude protein content of the feed should reach 35%. The feeding amount is generally 3% to 5% of the total fish body weight, fed once in the morning and once in the afternoon. Daily management work should be done well, keeping the dissolved oxygen in the pond water above 3 mg/L.
Catfish Breeding Techniques and Precautions
I. Breeding Techniques
1. Pond Conditions
The water quality is required to be fresh, with relatively high dissolved oxygen and a pH value of 7 to 8.2. Therefore, the pond should be selected in a place close to a water source, with convenient drainage and irrigation, and a quiet environment. The pond area is generally 1000 to 3000 sq m, with a water depth of 1.5 to 2 m, rectangular, running east to west, with the pond walls hardened with brick and stone or cement, the pond bottom sludge not exceeding 10 cm, and each pond equipped with one 3 kW impeller aerator.
2. Fingerling Stocking
Select artificially domesticated and bred one-winter-age fingerlings that are robust in constitution and uniform in size. Generally, 800 to 1200 fingerlings of 70 to 100 g are stocked per mu, together with 250 to 300 silver carp of 150 to 200 g and 75 to 100 bighead carp, plus 5 mandarin fish or bass to control wild trash fish in the pond. Do not stock competing fish such as common carp, grass carp and tilapia. Fingerling stocking is generally best in early March. 10 days before stocking the fingerlings, use 100 to 150 kg/mu of quicklime, slaked into slurry, and splash it over the whole pond, then after 7 days add water to the required water level. Before stocking the fingerlings, soak the fish body for 15 minutes in a 15 to 20 mg/L potassium permanganate solution or 3 to 5% salt water to kill pathogens and harmful organisms.
3. Feed Feeding
After the catfish have gone through the seedling stage and been trained to switch diets, compound feed is mainly used, with a crude protein content reaching 40 to 45%. The main raw materials are imported fishmeal, dried fish, soybean cake, peanut cake, wheat bran, yeast powder, mineral salts, vitamins, etc., made into hard pellet feed with particle sizes of 3 mm, 4 mm and 5 mm. At the beginning, the feed particle size is 3 mm, and as the fish gain weight, it is later changed to 4 mm and 5 mm. Feeding should be done at a fixed point, at a fixed time and in a fixed amount, and a feeding platform should be built on one side of the pond. After the fingerlings are stocked, they are trained: first train with sound at the feeding platform so that the pond fish form a conditioned reflex, then slowly feed by hand scattering. Feed twice a day, at 8 a.m. and 8 p.m., with the ratio of morning to afternoon feeding amount being 4:6. Each operation should be done carefully until the fish group has eaten its fill and leaves, and the daily feeding amount is generally 1.5 to 3%.
4. Water Quality Regulation
Catfish prefer pond water that is fresh and relatively high in dissolved oxygen. Usually, water quality management should be strengthened, insisting on frequently adding new water, starting the aerator in time, and reasonably using biological agents to regulate water quality. June to September is the peak growth season for catfish, so water should be flushed once every other day, and sewage discharged and water changed once a month, with the water change amount being 1/4 of the pond water. Increase aeration equipment as much as possible and start the aerator in good time. The operating times are: start at noon on sunny days, start in the early morning on cloudy days, start at midnight during continuous rainy weather; do not start in the evening, start early when floating head occurs, start every day during the peak growth season. The running time should be short at noon and long at midnight, short in cool weather and long in muggy weather, long when the load is heavy and short when the load is light. Regularly apply photosynthetic bacteria at 10 to 20 g/cubic meter. Regularly splash quicklime water; generally during the breeding period, splash once about every half month, with 5 to 10 kg per mu. Always keep the pond water dissolved oxygen not lower than 5 mg/L, the pH value at 7.2 to 8.2, and the water transparency at 30 to 40 cm, but this should be flexibly controlled according to the season and the fertility of the pond water quality. The water quality should not be too clear and lean; medium fertility, on the lighter side, is better. If the water source is abundant and the temperature is suitable, micro-flow water supplemented by regular flushing can also be used.
5. Daily Management
Patrol the pond diligently, insisting on patrolling in the morning, at noon and in the afternoon every day, removing residual feed, dirt and cleaning the feeding platform, and observing whether the pond fish show floating head. In the hot summer season and when the weather suddenly changes, also increase the number of nighttime patrols or arrange night shift management. Start feeding early: begin feeding and training the day after the fingerlings are stocked. Combined with pond patrols, observe the weather, the water color and the fish's feeding situation every day. Every 15 days, randomly sample fish bodies, check the fish's feeding and fatness, and by weighing and counting, estimate the fish's growth rate, the total amount of pond fish and the feed efficiency, so as to determine the feeding amount for the next stage.
6. Disease Prevention and Control
Every half month, splash quicklime over the whole pond once, with an amount of about 10 kg/mu. Add 1.5% allicin to the feed for a long time, and every month also make medicated bait with Yusukang and feed it for 3 consecutive days to prevent enteritis. Every month, alternately splash Lvshawang and copper sulfate over the whole pond, with the use concentrations being 0.2 to 0.3 g/cubic meter for Lvshawang and 0.3 to 0.5 g/cubic meter for copper sulfate. In feeding management, always pay attention to observing the feeding situation of the fish group, and if abnormal reactions or diseased fish are found, treat them with the right medicine as early as possible.
II. Precautions
1. Precautions for Feeding
Catfish have a primitive form of stomach and can store food for a short time. They are very voracious, so the feeding amount must be well controlled. Moreover, there are several periods when feeding requires special attention. One is before overwintering: do not stop feeding too early, to prevent the fish from being prone to disease after overwintering due to poor constitution. Another is the early-spring feeding resumption period: the feeding amount must be controlled, and it must be remembered that too great a change in feeding amount can cause stimulation, thereby causing intussusception disease.
2. Prevent the Occurrence of Intestinal Diseases
The intestine of catfish is short, and the size differs from front to back. In order to improve the intestine's absorption and utilization rate of feed and reduce the incidence of intussusception disease, intestinal health cannot be ignored. Feed in small amounts and more frequently; regularly use internal medicines to keep the intestine healthy and lower the feed conversion ratio.
3. Regularly Prevent Liver and Gallbladder Diseases
Under feeding conditions, the burden on the liver is very heavy. After excessive toxic substances in the water enter the fish body, they also need to be degraded and excreted through the liver, further increasing the burden on the liver. It is necessary to regularly eliminate toxins from the body and repair damaged liver, which can also effectively reduce the occurrence of hemorrhagic disease (especially in May and September and October during the small catfish breeding period, when prevention of hemorrhagic disease should be emphasized).
Main Causes of Saprolegniasis in Channel Catfish
1. Gas bubble disease damages the fish body, followed by secondary saprolegniasis. This is mainly because in early spring the water is shallow, and the water depth of most ponds is less than 1.5 m; large amounts of small algae reproduce in the pond, and when the weather is clear, the photosynthetic oxygen production capacity of the algae is strong, and dissolved oxygen in the middle and upper water layers is prone to supersaturation, making the cultured fish prone to gas bubble disease. In addition, during the overwintering period the pond accumulates a large amount of organic matter, the bottom quality is poor and the nitrogen content is high, which readily causes nitrogen supersaturation and triggers gas bubble disease, leading to damage to tissues such as fin rays, gills, eyes and skin, and infection with water mold when the water temperature drops.
2. Improper seine netting operations cause injury to the fish body, followed by infection with water mold. During the process of seining and sorting fish, there may be situations where, because only large fish are kept and small ones released or too many fish are netted, not all can be sold at once, so some are put back into the pond. Because the fish stay too long in the net bag, they are scraped and injured during the process. In addition, sometimes seining only sells the polycultured fish (silver carp, bighead carp, etc.), while the mainly cultured catfish are injured after being netted, and the injured parts ulcerate and then become secondarily infected with saprolegniasis.
3. Insufficient bait supply leads fish to cannibalize each other, and the wounds become infected with water mold. Catfish are omnivorous fish with a carnivorous tendency, and they can begin feeding when the water temperature is above 5°C. At this time, if feeding is insufficient, catfish may cannibalize each other, and the caudal fin area is very easily injured and develops tail rot. In early spring, seining in most ponds will reveal fish with incomplete caudal fins or large numbers of red-spot-like ulcers, with other parts intact, and the injured and ulcerated areas of the caudal fin become infected with water mold.
How to Solve Saprolegniasis in Channel Catfish
1. Prevent gas bubble disease. (1) Sufficient water level: keep the water depth above 1.5 m, stabilize the water body, avoid massive reproduction of small algae, and reduce photosynthesis; (2) After rain clears, start the aerator at noon in time to aerate and balance the dissolved oxygen in the upper and lower water layers; (3) Aerate in good time: on clear days, often start the aerator to reduce gas bubble disease caused by excessive dissolved oxygen in the upper water layer due to algal photosynthesis; (4) Regularly improve the bottom of old ponds to reduce bottom pollution and avoid nitrogen supersaturation caused by excessive nitrogenous organic matter; (5) When necessary, use "Sujiean" to alleviate and prevent gas bubble disease.
2. Reduce seining injuries. Choose soft nets for seining operations, and reduce fish body injuries as much as possible when netting and picking fish; at the same time, carry out sterilization treatment in time after seining, and "Yongle iodine" can be used continuously for "disinfection" and sterilization 2-3 times to reduce bacterial diseases and saprolegniasis induced by seining injuries.
3. Feed in time. At this time catfish may not come to the water surface to eat, but in fact they still need to ingest bait. According to the situation, feed at a ratio of about 0.5% of the weight of the fish in the pond. If catfish feed underwater, the situation of killing each other due to lack of bait can be reduced, avoiding fish body injuries.
Raising catfish is a very hard and troublesome matter. Therefore, people who are about to join the catfish breeding industry and farmers who are already raising catfish must be able to raise catfish scientifically, and must be able to endure hardship, because breeding is long-term hard labor, and only by persevering can success be achieved.