How can fish live longer?

For fish farmers, there are four kinds of water: first, fresh water, that is, tap water that has just been dried or well water that has been drilled. Although this kind of water is clean, it is very different from the environment in which fish live in nature. Because there is no nitrifying bacteria community in the water, fish excreta and scattered food residues decompose into ammonia after corruption, and fish are easy to be poisoned. Second, the old water, light green or amber, is rich in humus and beneficial microorganisms and algae, and has established a good ecological circulation system. After nitrogen cycle, it is decomposed into nitrate which is harmless to fish. This kind of water is extremely beneficial to the growth of fish. The third is green water. There are too many organic matters in the water, cyanobacteria, green algae and brown algae multiply in large numbers, and the content of bacteria and microorganisms increases sharply. The water is thick green, and sometimes it smells bad, which can easily lead to the death of the whole tank of fish. The fourth is to return to clear water, also called biting clear water. It is because there are too many algae and microorganisms in the green water, which consumes the oxygen in the aquarium, causing the death of algae and aerobic bacteria, and turning the water into stagnant water without oxygen and a large number of anaerobic harmful bacteria. It can be seen that not all water is suitable for goldfish's life, and the most suitable water for goldfish's growth is old water. Hydroponics is the process of changing new water into old water. At present, most of the water we use for fish farming is tap water, so the first step of water cultivation is to remove the toxic substance-chlorine from tap water. The method of chlorine removal is relatively simple. After the water is filled, let it stand for 2-3 days, or dry it 1 day (in case of urgent need, add 0.5% per 100 kg of water). 63g of baking soda, namely sodium thiosulfate, can be used immediately). After the fresh water is dried, it should be put into a tank for filtration, so that the water pump can turn the still water into flowing water, and then put the fish into the tank. "Broken tank" is to put a few cheap, strong and easy-to-raise fish into a new tank. After a few days, fish excrement will be decomposed into ammonia in water, which is the same as adding ammonia to tap water. Too much ammonia will kill fish, so the most important thing to raise water is to remove ammonia from the water. Usually we use nitrifying bacteria to remove ammonia from water. Nitrifying bacteria can be added to water, but they need attachments to survive in water. If there is no suitable attachment, it is not good to add more nitrifying bacteria. They will die in water, and nitrifying bacteria usually attach to filter cotton or bottom sand. In fact, running water will naturally produce nitrifying bacteria in a few days, which is also the most commonly used method to cultivate nitrifying bacteria. The cultivation of nitrifying bacteria is the second step of hydroponics. Here is a brief introduction to the subtle chemical changes of nitrogen cycle and the working principle of nitrifying bacteria. After the fish enters the tank, it will discharge ammonia and other wastes into the water, and the ammonia concentration in the water will increase, so the nitrifying bacteria in the domestic water can decompose ammonia (note: it takes a week or more for nitrifying bacteria to form, so the fish will be seriously injured during this time). When the nitrifying bacteria community is formed, the ammonia concentration will be reduced to zero. However, it is not that simple, because nitrifying bacteria can only convert ammonia into nitrite, but it is also toxic to fish! So we should understand that the concentration of nitrite is increasing, while the concentration of ammonia is decreasing. So don't think that you can sit back and relax after the ecology is established. In order to reduce nitrite, it is necessary to change water regularly and quantitatively to reduce its concentration, so as to maintain a relatively stable ecology and keep the water in an old state. I also want to tell you that old water is what we pursue, and green water also has many benefits for goldfish. For example, green water can darken the color of goldfish, but there are too many algae in this water to see fish and it is not suitable for viewing. Moreover, when there are too many algae, the fish will lack oxygen, so we should pay attention to controlling the algae content in the water when raising goldfish with green water. First, diligent observation and early treatment. Generally, after fish are infected or attacked by pathogens, there is a process and some signs. For example, sick fish move slowly and often swim slowly on the water without gathering. If disturbed, it will surface after sinking slightly. There are also some fish that swim wildly when they are just sick, or they are gray and scaly. For another example, after the bleeding of white crucian carp, the wild small miscellaneous fish in the early fish pond died. When fish disease symptoms are found in fish ponds, measures should be taken in time to prevent the disease from expanding. Second, the correct diagnosis, the right medicine First, according to the climate characteristics, water source, fish source, polyculture ratio and density feeding management, the epidemic law of fish diseases over the years, fish appetite, exercise, body color and other conditions, conduct on-the-spot investigation and analysis. Then, the body surface, gill filaments, muscles, internal organs and other parts of the dead or dying fish are examined by naked eyes or microscopes. See if there are large parasites such as Chinese herring and anchor head herring on its body surface, or bleeding spots, scales falling off, rotten fins, anal swelling, etc. The gill and gill cover are congested and corroded, the color and mucus contents of gill filaments are parasitic, and the gill filaments are rotten and turbid. Is there ascites, intestinal inflammation, congestion, liver and spleen congestion after the fish belly is cut open? Skin the fish, whether the muscles are bleeding, etc. According to the specific symptoms of the examination, first diagnose the diseases or complications of parasites, bacteria and viruses, and then make a comprehensive analysis according to the performance of the sick fish to make a correct diagnosis and prescribe the right medicine. Third, accurate measurement, accurate measurement and accurate dosage are another key to the treatment of fish diseases. For external use, the volume of pool water when the whole pool is splashed should be accurately calculated, and the influence of water quality characteristics and water temperature at that time should be considered. For example, when there are many organic substances, the water quality is fat, and the water temperature is low, the dosage should be more. The calculation of pool water quantity should be based on the actual water surface and average water depth. The calculation of average water depth is based on the average of several different depths in the pond. The dosage of oral medicine is expressed by how much medicine is ingested per kilogram of fish. There are usually two calculation methods: by weight and by feeding rate, which should be used flexibly. When most fish in the pond eat heavily, it is more accurate to calculate according to the total weight of fish in the pond; When the fish in the pond are seriously ill or the weather is bad, resulting in loss of appetite, drugs should be mixed in the bait in a high proportion according to the estimated feeding rate to ensure that the sick fish who can still eat can eat enough drugs. When preparing drug bait, the loss of drug in water should also be considered. Pay attention to the estimation of the total weight of fish in the pond, and consider the proportion of growth and weight gain in each stage, and can't calculate the feeding amount of drug bait by putting fish species. Four, grasp the characteristics of drugs, scientific use of commonly used drugs for fish diseases has its own physical and chemical characteristics, storage and use should be rationalized to avoid drug failure due to improper storage and use. For example, which drugs can only be used externally, which drugs are effective for oral administration, and which drugs cannot be used together. Which drugs will be more effective in combination and which drugs will be affected by environmental factors. Bait should take into account the living habits of fish, and make different bait such as floating, sinking and particle. Generally, if herring and crucian carp are sick, they should be fed with heavy bait; It is better to feed floating bait or mixed medicine on grass fish. Silver carp diseases should be fed with particulate bait, and a certain amount of adhesive should be mixed during production to prevent the loss of drugs in water. After the medicine is fully dissolved, it should be sprinkled evenly in the whole pool, and the splashing time in the afternoon is better, because the water temperature in the afternoon is high and the efficacy is high. When spraying the medicine, it is gradually spilled from the upper wind to the lower wind, and the undissolved medicine left after spraying cannot be poured into the pool. Otherwise, fish will cause poisoning and death if swallowed. 5. According to the illness, the whole course of treatment is the fundamental guarantee to cure fish diseases. If there is not enough course of treatment, the pathogen can not be completely eliminated, and the effect of drug treatment can not be achieved. Therefore, adequate treatment is an important link to completely eliminate pathogens and consolidate the therapeutic effect. In practice, the course of treatment should depend on the specific types of diseases suffered by fish. For example, invasive diseases are caused by parasites. Generally, 1 ~ 2 days is a course of treatment, which can achieve the purpose of treatment. Such as bacterial and viral diseases, generally 3 ~ 5 days is a course of treatment. As for the number of courses of treatment, it depends on the severity of the disease and the urgency of the course. It takes two or three courses of treatment for serious and long-lasting diseases, otherwise the curative effect will not be complete and there is the possibility of recurrence of infection. Six, a few points for attention 1. Before feeding the bait, stop eating 1 day to make the fish hungry. After feeding the bait, you can eat quickly. 2. During the treatment and just after the cure, it is not advisable to change a lot of water for fish, so as not to stimulate the fish, cause stress reaction, aggravate the condition or cause recurrence. 3. The treatment of fish diseases should adopt the method of combining oral administration with external elimination, and the internal and external attack can not be achieved by oral administration alone. 4. When treating fish diseases, you can't use the same drug alone for many times, so as to avoid the pathogen's drug resistance, so you should use drugs alternately. 5. Once the disease occurs, no matter the treatment effect is good or bad, the loss is inevitable. Therefore, we should adhere to the prevention policy of "prevention first, treatment second" in peacetime. The glass jar should be placed in a ventilated, sunny place near the window. Attention should be paid to stocking density and reasonable arrangement should be made according to the size of containers. It is better to raise more than less. Because the indoor air circulation is not good, raising more water is easy to be turbid, which can easily lead to goldfish dying of lack of oxygen. If you have a pump, you can raise more. If the goldfish is found to have a floating head, it is necessary to turn on the air pump for oxygenation, especially at night. Live fish worms are the most ideal bait for fish farming, and the water quality is not easy to deteriorate. Dried fish worms and synthetic pellet feed can also be used. There are live fish and worms on the market now, but it is also very troublesome to buy them every day. For dried fish worms sold in the market, choose fresh and loose particles to feed the fish, and don't buy old and moldy dried fish worms to feed them. It is best to use full-price feed with complete nutrients for artificial pellet feed, which is sold in the market. In order to keep the water pure, the feeding amount should be strictly timed and quantified. Usually, it is advisable to feed 1 2 times a day, and each feeding amount should be eaten within half an hour. Don't feed too much bait. Feeding too much has two disadvantages: first, the fish is full, the metabolic level is improved, and the oxygen consumption is increased, which is easy to cause goldfish to die of hypoxia and suffocation; Second, the bait is left, which is easy to rot and ferment, making the water quality worse and causing hypoxia. In fact, goldfish are hungry, and there will be no problem if they are not fed for a week or two. It is very important to keep goldfish clean. It is necessary to suck off the accumulated slag with latex tube regularly, clean up the feces and residual bait at the bottom of the glass jar together with turbid water, and then slowly replenish the fresh water that has been left for one day. If water plants are found floating or rockeries are knocked down during operation, they should be restored to their original state in time. The longer the fish is raised, the more sediment will be deposited. Although it is removed every day, it cannot be completely removed. If the sediment increases and affects the clarity of the glass jar, it is necessary to completely change the water to clean the glass jar, so as to keep the water pure and easy to watch, and also to maintain a good living environment for goldfish. Generally, rectangular glass cabinets are used. Because of their small size, it is not advisable to leave more, and less should not be more. For example, in a container with a length of 40 cm, a width of 25 cm and a height of 30 cm, six to eight goldfish with a length of 5 cm to 7 cm can be raised. Adult fish with a body length of more than 8 cm should not be kept in small glass tanks, but in luxurious large glass tanks or ceramic tanks, and equipped with small oxygenators for standby to prevent hypoxia. The above stocking density is for reference only, but also depends on water temperature, fish size and water quality. This cannot be done mechanically. Generally speaking, if the fish is big, it is necessary to raise less; You can raise more in winter and less in summer; You can raise more when the water temperature is low, and raise less when the water temperature is high.