1. Floating head due to lack of oxygen
Floating heads caused by lack of oxygen generally occur in high temperature seasons, and are common in the middle of the night and early morning, mainly due to the lack of dissolved oxygen in the pond waters. There are four main factors that cause water anoxia.
(1) The stocking density of the fish in the pool is too high, a large number of feeding and fertilizing, resulting in excessive water quality, phytoplankton mass production, coupled with rainy days, phytoplankton photosynthesis is weak, the supply of dissolved oxygen in the water is less, at night The respiration of fish and plankton and the decomposition of organic matter require the consumption of large amounts of oxygen, which results in the dissolved oxygen in the water being greater than the supply, causing the fish to float.
(2) During the day, the sunlight is strong, the temperature is high, and thunderstorms occur in the evening. A lot of low-temperature rainwater enters the fish pond, causing the water temperature on the surface of the pond to drastically decrease, the specific gravity increases, and the sinking occurs. The water temperature in the lower layer rises with a small proportion and rises. Convective convection occurs in the lower water layer, and the spoilage substances in the pool are turned up, accelerating their decomposition, consuming large amounts of oxygen and causing oxygen deprivation.
(3) The pool water is white, with great transparency, few phytoplankton, many leeches, and almost all of the phytoplankton in the water, resulting in lack of oxygen due to lack of photosynthesis oxygen production sources.
(4) It is clear that there is no rain, water temperature is high, the water quality is too fat, the transparency is low, the oxygen between the upper and lower layers is large, and the lower “Oxygen Debt†is large. If the water is not filled with new water for a long time, the water quality is too fat or corrupt to cause hypoxia.
2. Floating head caused by ammonia poisoning or hydrogen sulfide poisoning
The floating head caused by ammonia or hydrogen sulfide poisoning occurs mostly in spring, late autumn and winter. Afternoon is full of sunshine, occurs when the temperature is high, and occasionally occurs in summer. Ammonia poisoning and hydrogen sulfide poisoning are mainly caused by the following reasons.
(1) Aged ponds, too many organic matter in the sediment, together with insufficient dissolved oxygen, low pH, decomposition of organic matter produce a large amount of ammonia and hydrogen sulfide, causing fish poisoning floating head.
(2) Feeding too much, the bottom of the residual feed sediment rots and decomposes to produce ammonia and hydrogen sulfide so that the concentration in the water is too high, causing the fish to float.
(3) The pool water is too thin, and the amount of phytoplankton in the water is less, because the dissolved oxygen is mainly derived from the photosynthesis of phytoplankton. When there are few phytoplankton, the dissolved oxygen is low, and the ammonia nitrogen can not be turned into non-toxic nitrite nitrogen through oxidation, thus causing ammonia poisoning in water accumulation. In addition, phytoplankton absorbs ammonia nitrogen as its own nutrient and grows. The amount of phytoplankton is small, and ammonia nitrogen cannot be effectively absorbed, causing ammonia accumulation to cause poisoning.
3. Floating head caused by ankle disease
There is no apparent seasonality in floating heads caused by axillary diseases. The diseased fish is dark in color, slow in action and unresponsive. In the absence of oxygen in the pool, the diseased fish first floats and gathers next to the aerator, and the floating head symptoms do not decrease after power on, and the anoxic floating head and toxic floating head The difference is that floating fish is only part of the fish in the pool, not all. The diseases of the sacral area are divided into bacterial gill disease and parasite-induced sacral lesions, which make the fish breathless and float.