CATDOLL : CATDOLL: Bighead carp hemorrhagic disease. Bighead carp, grass carp and tilapia die every day in ponds. When they die, their bodies turn red and bleed.

Bighead carp hemorrhagic disease. Bighead carp, grass carp and tilapia die every day in ponds. When they die, their bodies turn red and bleed.

Causes of hemorrhagic disease in bighead carp: First, the pond has not been thoroughly dried and disinfected for a long time; second, the pond water is too fertile, unfermented organic fertilizers (pig manure, medium manure, chicken and duck manure) have been applied for a long time, the water quality is acidic, the pH value is below 6, and quicklime or strong chlorine and bleaching powder are not regularly sprinkled in the pond; third, hemorrhagic disease is caused when fishing in the hot season. Preventive measures: ① The fish pond should be thoroughly cleaned and disinfected once at the end of each year, and 100 kg to 150 kg of quicklime should be sprinkled per 667 square meters. After being exposed to the sun for 3 days, the harmful organisms at the bottom of the pond can be killed. ② When the high temperature season from June to September each year comes, it is the peak growth season for silver carp and bighead carp, and it is also the high incidence season of hemorrhagic disease in silver carp and bighead carp. At this time, prevention work must be done. First, add clean water to the pond frequently, once every 10 to 15 days, and the transparency of the water should be controlled above 25 cm.

Only grass carp died in the mixed fish pond. The symptoms are: white gills, mucus, red anus, everything else is normal, disinfectants have been used, but more than 100 kilograms of fish still die every day

Mainly raise grass carp, and mix other fish! This type of mixed farming mainly feeds grass carp (including bighead carp) with grass, uses the feces of grass carp and bighead carp to fertilize the water, produces a large amount of detritus and plankton, and raises silver carp and bighead carp. Because green fodder is easier to obtain and the cost is lower, it has become the most common type of mixed farming in my country.

Large-sized fish are stocked per mu and sold on the market that year!

The stocking specifications are 60 grass carps weighing 500-750 grams each, 200 bream weighing more than 50 grams, 300 silver carps weighing about 150 grams, and 100 bighead carps weighing 200 grams, and 300 carps and crucian carps! The yield per mu will reach more than 1,000 catties, of course, it requires feeding and oxygenation, and strict management!

Specific breeding methods:

1. Pond fertilization: Pond fertilization is to supplement the nutrients and organic matter in the water, increase the number of detritus food chains and grazing chains, and serve as bait for filter-feeding fish, omnivorous fish, and herbivorous fish. There are two types of pond fertilization:

(I) Applying basal fertilizer

(ii) Applying topdressing fertilizer

(III) Fertilization method

1. Use organic fertilizer as the main fertilizer and inorganic fertilizer as the auxiliary fertilizer, and follow the principle of "grasping both ends and leading the middle". 2. Organic fertilizer must be fermented and decomposed. 3. Apply fertilizer in small amounts and frequently, and apply less frequently. 4. Apply phosphorus fertilizer skillfully to promote nitrogen with phosphorus. (You can apply a certain amount of phosphorus fertilizer for better results)

2. Feeding: Feeding a large amount of good quality bait is an important technical measure for high yield, high quality and high efficiency of fish farming. In terms of feeding technology, the "four fixed" feeding principle should be implemented.

1. Determine the quality. 2. Determine the quantity. 3. Determine the timing. 4. Determine the location.

Basic requirements for pond management: water quality should be kept "rich, active, and refreshing", and feeding should be kept "even, good, and sufficient". Rich: means that there is a lot of plankton in the water, and it is rich in organic matter and nutrients. Active: means that the water color is often changing. The water color has monthly and daily changes (i.e. changes in the morning, afternoon, and upwind and downwind). It shows that the dominant species of phytoplankton appear alternately, especially the phytoplankton that is easy for fish to digest is large in number, good in quality, and appears frequently. Refreshing: means that the transparency of the pond water is moderate (25cm~40cm) and the dissolved oxygen conditions in the water are good. Even: means that a sufficient amount of bait should be continuously fed throughout the year. Under normal circumstances, the amount of feeding before and after should not differ much. Good: means the quality of bait and fertilizer. Sufficient: means that the amount of fertilizer and feeding is appropriate, and the fish will eat up the feed within the specified time, and the fish will not be too hungry or too full.

The Basics of Pond Management

The following work should be done in daily pond management: 1. Regularly inspect the pond and observe the dynamics of fish. 2. Keep the fish pond clean and sanitary. 3. Determine the type and amount of feeding and fertilizer according to the weather, water temperature, season, water quality, fish growth and feeding conditions. And do a good job in fish disease prevention and treatment in a timely manner. 4. Control the filling and drainage of pond water, maintain the appropriate water level, and do a good job in drought prevention, waterlogging prevention, and escape prevention. 5. Do a good job in calculating and allocating the demand for feed and fertilizer throughout the year. 6. Plant green fodder by the pond (or feed field). 7. Use fishery machinery reasonably, and do a good job in the maintenance and electrical safety of fishery machinery and equipment. 8. Do a good job in pond management records and statistical analysis.

Pond Water Quality Management:

(I) Timely addition of new water: Regular and timely addition of water is an essential measure for cultivating and controlling excellent water quality. For intensive fish ponds, adding water has four functions: 1. Increase the water depth. 2. Increase the transparency of the pond water. 3. Reduce the antibiotics secreted by algae (especially blue algae and green algae). 4. Directly increase the dissolved oxygen in the water to make the pond water flow vertically and horizontally, rescue or reduce the floating of fish and increase appetite.

2. Preventing fish from floating and flooding the pond

(III) Reasonable use of aerators

(IV) Use water quality improvement machines to make full use of pond mud