What are the prevention and treatment methods for toxic water disease in fish?

Water is the air that fish breathe to survive. In recent years, water bodies have suffered pollution (such as excessive dissolved oxygen, excessive metals, water oxygen deprivation, etc.), causing toxic water disease in fish and resulting in mass deaths. The following methods can be used to diagnose and rescue fish suffering from toxic water disease in water bodies.

1. Toxic water disease from excessive dissolved oxygen

Excessive dissolved oxygen in water bodies can cause eutrophication, leading to bubble disease and many other illnesses in fish.

1. Harm and symptoms. Because too much unfermented fertilizer is applied to the water body, fine small bubbles of methane and hydrogen sulfide are decomposed at the bottom of the pond, and fry mistakenly swallow them as food. The main symptoms are that many small bubbles adhere to the fish gills, causing the fish body to float upward or lose balance; there are white bubbles in the fish intestines, or many bubbles attach to the body surface, fin rays, and gill filaments, and the fish body floats on the water surface, which can cause fish death in severe cases.

2. Prevention and treatment. When bubble disease occurs in a fish pond, first, quickly inject clean water while discharging part of the pond water; fish with milder illness can expel the bubbles; second, use 400-600 grams of salt per mu of water surface and sprinkle it evenly, and good treatment results can be obtained within a few hours; third, quickly move the fish into a new water body.

2. Toxic water disease from excessive heavy metals

1. Harm and symptoms. When pond water is polluted by substances such as heavy metal salts, or lacks certain nutrients (such as calcium and vitamin C, etc.), the nerves and muscles of fish are stimulated and deformities occur. Sick fish have curved bodies, sunken opercula, or deformities in the upper and lower jaws of the mouth and fin rays (also called curved-body disease). Sick fish grow slowly and become thin, and severe cases cause death. This disease mostly occurs in fry and fingerlings cultured in newly opened fish ponds.

2. Prevention and treatment. Adult fish generally do not suffer from this disease. Newly opened fish ponds are best used to raise adult fish for 1-2 years first, and then release @#@233@#@ fry or fingerlings; diseased ponds should be frequently changed with water to improve water quality, and at the same time feed nutrient-rich bait to quickly strengthen the constitution of sick fish.

3. Toxic water disease from water oxygen deprivation

1. Harm and symptoms. Oxygen deprivation in water easily causes toxic water disease from oxygen deprivation, also called pond turnover. If the oxygen in the water drops to the point where it cannot meet the physiological needs of fish, the fish can suffocate and die. If not rescued in time, it will cause mass death of fish.

2. Prevention and treatment. Properly control stocking density. In muggy weather, appropriately reduce feeding and fertilization. When clearing the pond in winter, dig out part of the sludge at the bottom of the pond to prevent excessive sludge at the bottom from affecting water quality. High-yield fish ponds should be equipped with aerators and aerate regularly. Feeding bait should achieve fixed quality, fixed quantity, fixed time, and fixed location, and leftover bait in the feeding area should be removed in time. If fish are found floating at the surface, new water should be injected immediately, and the water inlet should be covered with reed mats or wooden boards so that the water does not directly hit the pond bottom and stir up sludge. When necessary, the pond fish can be transferred to another pond, or chemical oxygen generators can be used to increase oxygen.