The main causes of non-disease death of koi and its solutions

I. Water quality

At present, the water used for family culture of koi is mainly tap water, and the source quality of tap water in some areas is poor. Waterworks use a large number of disinfectants and cleaners during treatment, and the fish will be poisoned if they do not adapt to the change of water. that's why there are water treatment links such as sun water and aeration before changing water. Chlorine in water is the main cause of fish poisoning. In the process of changing water, the method of gradual addition should be adopted as far as possible, the change of water should be completed several times, and sodium thiosulfate should be properly put into the water to remove the residual chlorine.

Koi like to live in a water environment with low hardness, and koi can be raised in both soft and hard water. In general, tap water is soft water, and groundwater (spring water, well water) is hard water. In the process of transporting fish species or breeding koi, you should avoid suddenly moving from soft water to water with higher hardness, so as to avoid allergic reactions.

To a certain extent, water color can reflect the quality of water quality. The water quality of the tender green water is relatively good, and the daily timely discharge or the regular addition of photosynthetic bacteria to the aquaculture water body can keep the water color fresh.

Second, the temperature difference of the environment

Although koi can survive at a water temperature of 2-30 ℃, its adaptability to the sudden change of water temperature is very poor, and it is easy to die suddenly when the temperature difference is more than 3 ℃.

After the fry is bought, it can not be put into the fish tank or other aquaculture water immediately. Generally speaking, the koi fry together with the fish bag should be put in the water to be raised for 20 minutes, and then slowly inject new water into the bag to gradually replace the water in the original fry bag. This process, commonly known as "warm seedlings", can effectively reduce the sudden death of fish fry caused by temperature difference.

In home farming, if you want to change water urgently when it is cold (especially in the northern areas), you can first use a water heater to heat the new water, slowly pour it into the fish tank, and use a thermometer to measure the temperature change in real time.

III. Poisoning caused by excretion of waste

Due to the metabolism of koi, the excreted waste and residual bait are deposited in the water body, and the nitrite, ammonia nitrogen, hydrogen sulfide and other harmful substances produced by these wastes through various ways are dissolved into the water body, which leads to the physical decline and poisoning of koi after continuous accumulation. When the concentration of harmful substances is too high, the activity of koi weakens and floats to the surface of the water, the body color becomes lighter, and then a large number of deaths occur. The accumulation of these harmful substances will not only poison the koi to death, but also breed a large number of bacteria. This is also one of the main causes of fish disease. The main ways to solve the problem are as follows:

1. Careful selection of feed

Some feeds are produced with deteriorated animal bone meal and corpses, which are easy to produce ammonia after feeding, so you can't choose feeds with rotten flavor when you buy them.

two。 Control the amount of feeding

The control of feeding amount is an important part of raising koi. The residual bait produced by excessive bait will not only cause waste, but also cause decay, produce harmful substances, threaten the survival of koi, and is not conducive to maintaining the shape of koi. In general, bait should be controlled within 10 to 20 minutes for the fish to eat for the degree, bait feeding should not be excessive. The feces of koi can be used to observe whether there is too much feeding, and if the faeces become hard, it means too much bait. The best feeding times are once in the morning and once in the afternoon (bait should be given in the morning in summer). The feed mixed with fish meal and malt is easier to digest, and a few slices of enzymes can also be added to the diet to aid digestion.

3. Add salt properly

When adding water, adding salt at 0.2%-0.3% of fresh water can not only inhibit the growth of some harmful bacteria, but also provide salt for the normal metabolism of fish and reduce the production of waste.

4. Adding microorganisms to decompose pollutants in water

Microorganisms such as nitrifying bacteria, photosynthetic bacteria and Bacillus subtilis can decompose the feces and residual bait of koi, making the bacteria lose nutrition. Regularly sprinkling these beneficial microorganisms can effectively reduce the content of nitrite and ammonia nitrogen in water, so it is also called "water purification bacteria".

When using the water purification bacteria, we should pay attention to the water temperature above 23 ℃ and the pH value above 7.0. the acid water is not conducive to the growth of water purification bacteria. Water purification bacteria are living bacteria, drugs can kill it, can not be used at the same time with disinfection fungicides. If it is necessary to use fungicides or drugs to treat fish diseases, wait for at least a week before using water purification bacteria. The use of photosynthetic bacteria should also pay attention to do not use in overcast and rainy days, so as to form a dominant community in the water and give play to the best effect. In addition, if you want to keep different water purification bacteria at the same time, you should pay attention to the compatibility between bacteria. For example, nitrifying bacteria and photosynthetic bacteria are not suitable to be kept in the same aquarium at the same time, because they inhibit each other in the process of water purification, which may reduce their purification effect.

5. Strengthen the cleaning of the filter box

In the process of breeding, the filter box should be cleaned once or twice a day. When cleaning, turn off the circulating pump, open the drain pipe of the filter box, completely empty the whole box, and then wash the dirt on the filter material with a separation pump. If the dirt in the filter box accumulates too much and the bacteria cannot decompose the dirt in time, the water becomes turbid and foams occur. These foams are mainly caused by the high content of bacteria, organic matter and ammonia nitrogen waste.

4. Death of koi caused by hypoxia

Koi is sensitive to dissolved oxygen, which will be affected by the mass reproduction of green algae and moss in water. Try to avoid putting the aquarium on the windowsill, strictly control the lighting time, take 8-10 hours a day, and do not use it continuously for more than 13 hours, which will cause the sharp growth of aquatic plants and the lack of oxygen in the water. The death of moss and the emission of carbon dioxide and hydrogen sulfide from aquatic plants without light will also pollute and poison the aquaculture water, resulting in the death of koi. Fish tanks that do not cultivate water purification bacteria can be equipped with ultraviolet disinfector to kill bacteria and algae.

In addition, the culture water temperature should not be too high, the higher the water temperature, the more oxygen consumption of Koi metabolism.

5. Death from trauma caused by cylinder jumping

Koi jumping is also one of the common causes of abnormal death. Koi is a jumping fish with strong strength. The top of the tank had better be protected. If there are many edges and corners at the top of the tank, it should be blocked by glass or soft plate. When aquarium culture, do not suddenly switch on and off the lighting equipment on the top of the box, otherwise the koi will be easily frightened, jump out of the water and touch the lid or wall of the box and cause injury.