Floating head generally refers to the phenomenon that the dissolved oxygen content in the water drops sharply due to changes in the water environment, causing fish to float on the water surface and swallow air due to lack of oxygen. Fish floating head is a temporary physiological stress response to hypoxia and other adverse factors in the water environment. A slight floating head can affect the growth rate of fish, and a severe floating head will cause a large number of fish deaths. If not rescued in time, it can cause Farmers to suffer significant economic losses, so floating heads are a “red flag” in aquaculture production. Pond farming of tilapia is currently the most widespread and popular method of tilapia farming. Due to the small area, high flexibility, and low cost of pond farming, tilapia farming in ponds has become a major source of income for farmers. One of the important ways to get rich. Generally, there are many reasons for the floating head phenomenon of tilapia cultured in ponds. The following reasons are more common.
Tilapia with hepatobiliary syndrome also have floating symptoms, disordered activities, or swirling or drilling up and down.
Treatment: Symptoms can be relieved by changing floating fish feeds with lower protein content. It is recommended to add an appropriate amount of choline chloride to the feed to prevent and treat this disease.
The bottom of the intensive pond has been silted for many years, and the bottom mud is generally thick, which hides a large number of plankton and protozoan eggs. After the water temperature warmed up in spring and the pond was cleared with quicklime and fertilized, these eggs were quickly activated and proliferated in large numbers, resulting in a great increase in the respiration and oxygen consumption in the pond, while the phytoplankton with the function of oxygen production became increasingly scarce, and the pond water quickly became dirty. , the water is off-white or light brown. This situation often occurs in the early stage of tilapia fry cultivation. At the same time, because the water temperature is not very high at this time, the floating head symptoms are not very obvious, and it is often ignored by people, resulting in dead fish accidents.
Treatment: Kill the excessive zooplankton with the national standard insecticide and immediately fertilize the water. Combined with potassium hydrogen persulfate to improve the bottom to create a good water environment to balance plankton.
A large amount of unfermented manure was applied to tilapia in the early stage of pond culture, plus the accumulation of excessively thick silt and feed residues, the pond water is generally very fertile. Decomposition consumes a large amount of oxygen. In this case, the dissolved oxygen in the water is consumed in a large amount, and the lack of oxygen in the pond causes the tilapia to float.
Treatment: dredging once every 2-3 years if conditions permit. Feeding and management, and removal of feed residues. The use of organic fertilizers should be applied in a small amount after full fermentation. Control the feeding and rationally use polyaluminum chloride or large soda to absorb macromolecular particles in the water body, and turn on the aerator reasonably.
In the middle and late stages of tilapia culture in ponds, the pond water often grows a large number of blue-green algae due to excessive fertilizer, and the water is blue-green or dark green. A layer of organic floating film often floats 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 body. In the event of sudden changes in weather or other reasons, blue-green algae and other aging die and sink. The pool water is layered: the bottom layer is dark and fat, while the upper layer is very transparent. The dissolved oxygen in the whole pool is very low, and the toxic substances increase significantly, and the fishy odor can be smelled in the downwind. If not rescued in time, severe tilapia floating head, pan-pond or even extinction will occur.
Treatment: Observing frequently in ponds, when it is found that the pool water is dark and aging, the lower water should be drained immediately and new water should be added to rescue and use sodium percarbonate + organic acid + ginger ketone to reduce losses. When the fish is in the lower layer, supplement the bacteria and algae fertilizer more than 2 times on sunny days. Extend the start-up time of the aerator and remove harmful gases.
Generally, thunderstorms and cold winds in the evening on a sunny day will cause convection in the upper and lower layers of the pool water in advance. Causes tilapia to float. In continuous rainy weather and insufficient light, the photosynthesis of phytoplankton is weak, and the dissolved oxygen in the water cannot be adequately supplemented, while the respiration of farmed fish and other aquatic organisms continues as usual, thus causing floating heads.
Treatment: Pay attention to the weather forecast. In case of rainy and muggy weather, you should put less or no bait in the afternoon. At night, you should check the pond and turn on the aerator or flush the water the next morning.
Some inexperienced fishermen stock tilapia fingerlings without frequent cleaning or disinfection of ponds, and do not set up filters when irrigating, and all kinds of wild fish and insect eggs are put into the pond together , resulting in excessive biological density in the pond water, resulting in tilapia anoxic floating head. When we knew that the water quality had become bad, we did not plan for the worst, especially in the high temperature season, the dissolved oxygen content in the water decreased with the increase of water temperature, while the respiration intensity of tilapia increased accordingly, making the water in the pond water. When the oxygen consumption is greater than the source, it is reasonable for the tilapia to float.
Treatment: Arrange the stocking density reasonably according to the specific situation. To clean the pond, set up a sieve filter bag at the water inlet when irrigating to prevent wild fish and insect eggs from entering the pond. Kill excess zooplankton with insecticides if necessary.
chemical products such as copper sulfate and ferrous sulfate were used frequently by many farmers in aquaculture in the past, but they must master the amount and time of use when using them. Once used improperly, these medicines will not only not cure fish diseases, but will also have counter-effects. Mistakes will lead to pollution of water or improper dosage of medicines, and the floating head caused by excessive dosage will not only float, but will also jump or go crazy. tour.
Treatment: Quickly introduce new water to dilute the concentration of harmful substances. Quickly find out which drugs correspond to detoxification products.
When a large number of parasites or protozoa are parasitized on the gills of fish, it often affects the respiration of fish, floating on the water surface, clearly visible, and roaming in groups.
Treatment: take anthelmintics orally, and use targeted national standard insecticides externally.