"Does the fish float have to be hypoxic? What is hypoxia?"

"Is the floating head a lack of oxygen? What should I do if I am deprived of oxygen? What is the reason for the floating head of the water hypoxic fish?"

"There are many cases that cause fish to float, and they can't all be attributed to lack of oxygen. I'll check it for you as soon as possible. Gu Fanxin opened his mobile phone Baidu to learn about this.

“…… When the density of fish is too high, it is especially easy to float at night.

At night, algae have no way to photosynthesize and produce oxygen, in addition to the dissolved oxygen in the pond will be consumed by the respiration of zooplankton, most of the remaining dissolved oxygen will be consumed by the respiration of fish, too many fish will accelerate the consumption of dissolved oxygen, and when the dissolved oxygen is too low, there will be a fish floating head phenomenon.

This situation can be alleviated by simply turning on the aerator and sprinkling the aerator powder.

More than 80% of the dissolved oxygen in the pond comes from the photosynthesis of algae, and there are not many algae in the pond, and the oxygen production capacity is insufficient, which means that the fish do not get enough oxygen to breathe, so they will float their heads and breathe air to replenish the oxygen in the body.

The water is too fertilized. Although more than 80% of the dissolved oxygen in the pond comes from the photosynthesis of algae, but more than 70% of the dissolved oxygen in the pond is also consumed by algae, when the water quality is too fertilized, the dissolved oxygen in the pond changes greatly day and night, the dissolved oxygen is very high during the day, up to more than 14 mg/L, if it is a fish fry pond, it is easy to get bubble disease, and it is very low at night, as low as 3 mg/L, resulting in anoxic floating head of fish.

This kind of pond can be adjusted by changing the water and using bacillus, although copper sulfate, bleach powder and other drugs can kill algae, but it is not recommended to use, it is easy to pour algae.

The silt is thick. Long-term unsilted ponds, the bottom silt will consume a large amount of dissolved oxygen, easy to cause nitrite exceedance, when there is a floating head phenomenon, the probability of saving the pond with thick silt is lower than that of the pond that is dredged every year.

Heavy rainfall for a short period of time. A short period of heavy rainfall will lead to convection up and down the water body, the upper water dissolved oxygen is sufficient, the water body up and down convection, the upper water dissolved oxygen will be used to repay the oxygen debt at the bottom, at this time the dissolved oxygen of the whole water body is relatively low, which is also one of the main reasons why the sudden rainstorm after continuous high temperature is easy to turn over a large number of ponds.

Consecutive rainy days. The main drawbacks of continuous rainy days are lack of sunlight, low algae productivity in ponds, and less oxygen production.

However, there are not many hypoxic floating heads, mainly because the temperature is low on rainy days, whether it is algae, zooplankton and farmed fish, the oxygen consumption for respiration is relatively small.

However, it is necessary to be vigilant, once a large area of floating head occurs at this time, it is difficult to avoid the end of turning over the pond, therefore, in the event of continuous rainy days, the number of bottom changes needs to be increased and the amount of feeding should be reduced.

The dissolved oxygen in the water is not low, and the fish still floats

When the dissolved oxygen in the pond is not low, sometimes there will be a floating head phenomenon, which is generally caused by the reduction of the oxygen-carrying capacity of the fish blood, such as parasites, ammonia nitrogen exceedance, nitrite exceedance, etc.

1. Parasites. Gill parasites such as wheel worms, ring worms, third-generation worms, and Chinese eel can destroy the gill structure of fish, resulting in physiological hypoxic floating head of fish.

When there are more wheel worms, fish generally swim around the pond, commonly known as "horse race";

When there are too many ring worms and three generations, the fish are restless and sometimes jump.

2. Ammonia nitrogen exceeds the standard. Too high ammonia nitrogen will affect the respiratory system of fish, mainly gills and swim bladders, so that its ability to absorb and utilize oxygen will decrease, and it will cause red and swollen gills for a long time, and too high will lead to death of fish ammonia nitrogen poisoning, and the use of photosynthetic bacteria can control ammonia nitrogen.

3. Excessive nitrite. Nitrite binds to oxygen-carrying proteins in the blood system, resulting in a decrease in its oxygen-carrying capacity and deprivation of oxygen.

If the aerator is turned on, the fish will generally not surround the aerator and swim around as before, and the food is generally poor.

Fish floating head is a temporary physiological response to the lack of oxygen and other adverse factors in the water environment, if effective measures are not taken in time, it will gradually aggravate or even flood the pond, causing major economic losses.

The fundamental approach should be to find out the cause (floating or floating) and treat it in a targeted manner.

10 types of fish float countermeasures

1. Floating head caused by water thinness. After years of siltation, the sediment of the intensive high-yield pond is generally thick, which hides a large number of plankton and protozoan eggs.

After the water temperature warms up in spring and the quicklime pond is cleared and fertilized, these eggs are quickly activated and multiply in large quantities, resulting in a great increase in the oxygen consumption of respiration in the pond.

However, phytoplankton with oxygen-producing functions are becoming scarce, and the water quickly becomes thinner, grayish-white or light brown.

(1) Use national standard insecticides to kill excessive zooplankton and immediately fertilize water.

(2) Combined with potassium persulfate bottoming, create a good water environment and make plankton balance.

2. Floating head caused by water and fertilizer. A large amount of unfermented manure is applied in the early stage, coupled with the accumulation of too thick silt and forage residues, the pond water is generally very fertile, and after the water-saving temperature rises sharply in summer and autumn, the fermentation and decomposition of fertilizer and organic accumulation consumes a large amount of oxygen.

In this case, a large amount of dissolved oxygen in the water is taken away, and hypoxic floating heads are inevitable.

Countermeasures: (1) Conditional dredging once every 2~3 years. In the feeding management, the forage residue should be removed in time, and the organic fertilizer should be fully fermented and applied in small quantities.

(2) Control the feeding and reasonably use polyaluminum chloride or baking soda to adsorb macromolecular particles in the water, and reasonably open the aerator machine.

3. Floating head caused by water transfer. In the middle and late stages of aquaculture, a large number of blue-green algae often grow in the pond water due to over-fertilization, and the water is blue-green or dark green.

A large amount of harmful gases such as hydrogen sulfide, methane, ammonia nitrogen, etc., accumulate at the bottom of the pond to poison the water body.

The water of the pond is stratified, the bottom layer is dark and seems to be very fat, while the upper layer of water is very transparent;

The dissolved oxygen in the whole pool is very low, and the toxic substances increase significantly, the downwind can smell the fishy smell, and the water quality deteriorates quickly, that is, the so-called water quality corruption or "water transfer", if not rescued in time, there will be serious floating heads, flooding ponds and even extinction.

(Frequent patrol of the pond observation, when it is found that the pool water is dark and aging, the lower layer of water should be immediately drained, new water should be added to rescue, and the three treasures of fishery rescue (sodium percarbonate + organic acid + ginger ketone should be used to reduce losses).

(2) When the fish is in the lower layer, supplement the algae fertilizer more than 2 times on a sunny day.

(3) Extend the start time of the aerator and eliminate harmful gases.

4. Floating head caused by weather changes. Thundershowers, cold winds or aerators in the evening on sunny days will cause the upper and lower layers of the pool water to convection in advance, and the surface water with high dissolved oxygen will sink to repay the oxygen debt;

The bottom water is mixed with various harmful gases and even sediment, resulting in a lack of oxygen in the whole pool and causing a floating head.

In addition, continuous rainy weather, insufficient light, weak photosynthesis of phytoplankton, and insufficient replenishment of dissolved oxygen in water.

However, the respiration of fish and other aquatic organisms proceeds as usual, resulting in floating heads.

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

5. Floating heads caused by excessive density of fish and other aquatic organisms. Some inexperienced fishermen stocked fish fingerlings without cleaning and disinfecting the pond, and did not set up a filter screen when irrigating, and all kinds of wild trash fish and insect eggs were combined into the pond, resulting in excessive biological density in the pond and making the fish hypoxic floating heads. ”