Several situations of floating head of fish and their countermeasures

Fish floating head is a temporary physiological adaptation to hypoxia and other adverse factors in the water environment. If effective measures are not taken in time, it will gradually increase or even flood the pond, resulting in significant economic losses. Fish floating head includes a variety of reasons, first aid measures should also be based on the situation before it can be effective. Generally speaking, turning on the aerator and flushing and replacing the new water is effective for the floating head in most cases, but in some cases, these methods can only play a temporary role in relieving the symptoms rather than the root causes. The fundamental solution should be to find out the cause (floating head or floating) and treat it in a targeted manner.

Floating head caused by thinness of water

After years of siltation in intensive culture high-yield ponds, the sediment is generally thick, in which a large number of plankton and protozoan eggs are hidden. After the water temperature warms up at the beginning of spring and is sterilized and fertilized with quicklime, these eggs are quickly activated and multiply in large numbers, resulting in a great increase in oxygen consumption in the pond. On the other hand, there is a growing shortage of oxygen-producing phytoplankton, and the pool water quickly becomes thinner, and the water is grayish white or light brown. This situation often occurs from April to May and in the early stage of seedling cultivation. At this time, the water temperature is not very high and the symptoms of floating head are not very obvious, so it is often ignored by people and cause accidents. Countermeasures:

1. Kill too many zooplankton with insecticides and fertilize and water immediately.

2. Remove too much sludge from the pond, apply organic base fertilizer in the shoal as early as possible, and drag it repeatedly with iron rake to accelerate fermentation decomposition and avoid excessive accumulation.

Floating head caused by water and fertilizer

In the early stage, a large amount of unfermented manure was applied, coupled with the accumulation of thick silt and forage residue, the pond water was generally very fertilized. after the water temperature rose sharply in summer and autumn, fertilizer and organic accumulation consumed a lot of oxygen by fermentation. In this case, a large number of dissolved oxygen in the water is taken away, and hypoxia floating head is inevitable. Countermeasures:

The main results are as follows: 1. Dredging once every 2 ~ 3 years. In feeding and management, the residue of forage grass should be removed in time. The use of organic fertilizer should be applied frequently after full fermentation, chemical fertilizer should be given priority to in high temperature season, and chemical manure soup should be sprinkled at noon on sunny days after fermentation.

2. Flush fresh water regularly and turn on the aerator reasonably to keep the water quality "fat and tender".

Floating head caused by turning water

In the middle and later period of culture, the pond water often produces a large number of blue-green algae because of excessive fertilizer, and the water is blue-green or dark green. A layer of organic floating film is often floating in the downwind, and a large amount of harmful gases such as hydrogen sulfide, methane and ammonia nitrogen accumulate at the bottom of the pool to poison the water. In case of sudden changes in the weather or other reasons, blue-green algae and other aging death and sinking. The pool water is stratified: the bottom layer is dark and fat, while the upper layer is very transparent. The dissolved oxygen in the whole pond is very low, while the toxic substances increase significantly, the fishy smell can be smelled in the downwind, and the water quality deteriorates quickly, that is, the so-called water quality is deteriorated or "transferred". If it is not rescued in time, serious floating heads, flooding ponds and even extinction will occur. Countermeasures:

1. Patrol the pond frequently and observe. When it is found that the pond water is dark and aging, you should immediately rinse new water or use quicklime to adjust the water quality.

2. Once the transferred water is transferred, the bottom water should be discharged and filled with fresh water, and the amount of water should be changed by 1 × 3 × 1 / 2, and quick-acting chemical fertilizer should be applied at the same time to make the water and fertilizer get up as soon as possible and increase the dissolved oxygen.

3. Prolong the start-up time of the aerator and remove harmful gases.

Floating head caused by weather change

On a sunny evening, a thunderstorm, a cold wind, or turning on an aerator will make the upper and lower layers of the pool water convection ahead of time, sink the surface water with high dissolved oxygen and repay the oxygen debt, while the bottom water is mixed with all kinds of harmful gases and even sediment, causing hypoxia in the whole pool and causing floating heads. In addition, due to continuous overcast and rainy weather, insufficient light, weak photosynthesis of phytoplankton and insufficient replenishment of dissolved oxygen in water. On the other hand, the respiration of fish and other aquatic organisms continues as usual, resulting in floating heads.

Countermeasures: pay attention to listen to the weather forecast, in case of cloudy, rainy and muggy weather, you should take less bait or no bait in the afternoon, patrol the pond at night, turn on the aerator or flush the next morning.

Floating heads caused by excessive density of fish and other aquatic organisms

Some inexperienced fishermen release their fish species without clearing the pond for disinfection, and they do not set up a filter when they are irrigated, and all kinds of wild fish and insect eggs go into the pond together, resulting in excessive biological density in the pond and anoxic floating heads of fish. Especially in the high temperature season, the solubility of oxygen in water decreases with the increase of water temperature, while the respiratory intensity of fish increases. In this case where the oxygen consumption is greater than the source, the floating head is reasonable. Countermeasures:

1. Arrange the stocking density reasonably according to the specific situation.

2. To clean and disinfect the pond, a sieve silk filter pocket should be set up at the water inlet to prevent wild fish and insect eggs from entering the pond.

3. Kill too many zooplankton with insecticides if necessary.

Floating head caused by ammonia nitrogen poisoning

Ponds with more dead fish in the previous crop and not fished out in time, or ponds that inadvertently apply too much chemical fertilizer, often cause ammonia nitrogen and other harmful substances to exceed the standard, resulting in floating heads. But this kind of floating head mostly occurs at noon. Fish move slowly, and they will die over time. Countermeasures:

1. Rinse fresh water immediately and turn on the machine to increase oxygen and detoxify.

2. Apply photosynthetic bacteria or Tangdujing to improve the bottom quality, but do not use alkaline drugs such as quicklime.

Floating head caused by misleading contaminated water or excessive dosage

In addition to floating, it will also jump or swim wildly.

Countermeasures: introduce new water quickly and dilute the concentration of harmful substances.

Floating head caused by diseases and insect pests

When a large number of parasites or protozoa are parasitized on the Gill of fish, it often affects the respiration of fish, rises to the surface, is clearly visible, roams in groups, and occasionally has spinning symptoms, especially grass carp.

Countermeasures: continuous use of insecticides for 2 or 3 times.

A floating head caused by hunger

When the water quality is thin and natural bait is lacking, silver carp and bighead carp will float in groups to find food, grab feed powder and swallow organic floating film, but they move quickly and swim freely, not caused by hypoxia.

Countermeasures: timely topdressing, accelerate the reproduction of plankton, can also be fed with powdered concentrate.

Floating head caused by hepatobiliary syndrome

Grass carp and common carp with hepatobiliary syndrome also have symptoms of floating, disorderly movement, or spinning or drilling up and down. No obvious symptoms were found on the body surface, but after dissection, the liver showed white and yellow spots, bile enlargement, dark black, and the fish died one after another. Countermeasures:

The main results are as follows: 1. The symptoms were relieved after the replacement of lower protein diet.

2. It is suggested that the disease can be prevented and treated by feeding Ligan bait or adding proper amount of choline chloride to the feed.

Prevent fish from floating head and look for signs as early as possible

Fish always have certain signs before floating head. Mastering these rules is helpful to do a good job in the prevention of floating head and achieve the purpose of reducing economic losses.

1. Forecast according to the weather forecast and the weather conditions of the day: in summer, in case of continuous rain, low pressure, weak wind, heavy fog and other adverse weather, when the weather turns cloudy in the evening, thundershowers or water quality changes suddenly, floating heads may occur the next morning.

2. Forecast according to the characteristics of the season: in general, the water temperature increases gradually in spring and summer, the food intake of fish increases gradually, the water quality gradually turns fertilizer, the storage capacity of pond fish is large, and floating heads are easy to occur in case of sudden changes in weather. In continuous overcast and rainy weather in summer, the light intensity is weak and the photosynthesis of phytoplankton is not strong, so floating head is the most likely to occur. In autumn, the adult fish have reached the commercial specifications, and the storage capacity of the adult fish in the pond is large, and the water quality is fertilized. although the temperature drops day by day, the oxygen consumption of the pond water body is increasing, and floating heads are easy to occur when the weather changes slightly.

3. Forecast according to the water quality: in summer, the concentration of plankton in the water is high, if the weather changes suddenly, especially the temperature drops suddenly, it is easy to cause a large number of plankton to die and the water quality to become clear suddenly. At this time, the oxygen consumption factor in the water increases rapidly, and serious floating heads and even flooding ponds often occur.

4. The prediction is made according to the feeding situation of the fish: if there are less fish to eat when feeding, and no fish disease is found, it can be concluded that the water quality of the fish pond is not good and the amount of dissolved oxygen in the water is low. This phenomenon is usually more obvious during the first bait meal in the morning; if the same is true for the last meal in the afternoon, the possibility of floating head early at night is very high and should be paid attention to.

It can be judged by observing the feeding condition of grass carp. Under normal circumstances, grass carp usually feed in the food field and can only see the grass pile turning or the grass being dragged to the surface of the water. If grass carp eat at the edge of the haystack, or even swim in the pond with their mouths full of grass, it is also a sign of low dissolved oxygen in the pond, in which case floating heads are easy to occur.