What are the treatment methods for gas bubble disease in fry
Treatment of gas bubble disease in fry
Treatment of gas bubble disease in fry
Gas bubble disease in fry is a common disease. In the early stage of the disease, the sick fish swim weakly at the water surface, and soon bubbles appear on the body surface, head, fin rays, gill filaments or inner intestine of the sick fish. When the bubbles are not large, the fish can still resist their buoyancy and swim downward, but the body loses balance, with the tail upward and the head downward, swimming and stopping intermittently. As the bubbles enlarge and the fish's strength is consumed, the sick fish float at the water surface and cannot sink, until death.
So why do fry suffer from gas bubble disease? Ponds for raising fry must be thoroughly cleared before stocking; generally quicklime (125 kg per mu) is used for disinfection, followed by a period of sun-drying. However, after sun-drying, the pond bottom is very loose, and after filling with water many small bubbles are produced; if fry swallow them by mistake, gas bubble disease is caused. Therefore, before fry are put into the pond, a fishing net or a thick long wooden pole must be used to pull back and forth several times in the pond; the water quality must be kept fresh and must not be too fertile.
It is worth noting that manure must be fully fermented before being applied to fry ponds. This is because manure that is not thoroughly fermented will slowly decompose after being applied to the fish pond, consuming oxygen in the water, while also continuously releasing methane and hydrogen sulfide gases that form extremely small bubbles, which are easily eaten by mistake by fish and cause gas bubble disease.
When gas bubble disease occurs, a two-pronged rescue measure should be taken for the affected fry: first, quickly add fresh water; second, for each mu of pond, use 4 kg of crushed gypsum, 4 kg of fresh tender Asiatic plantain, and 5 kg of soybean, soak them in water until swollen, grind them together into a slurry, and splash it over the whole pond, once every 2 days. After splashing 4 times in this way, the sick fish recover.
Now it is again the season for winter stocking of fingerlings. Although winter stocking of fingerlings has many advantages, it must be noted that if the dissolved gas in the pond water is overly saturated, or bubbles are continuously produced in the pond water and are swallowed by mistake by the fry, gas bubble disease is likely to occur. In production, the following methods can be used to prevent and treat gas bubble disease in fry:
① Keep the water quality fresh and control the amount of phytoplankton in the pond water so that it does not reproduce excessively;
② Before releasing fry, remove excess sludge from the pond, do not apply organic fertilizer that has not been fully fermented and decomposed, correctly master the amount of fertilizer and feed, and promptly remove decaying matter in the pond;
③ Groundwater introduced into fry ponds must first undergo full aeration;
④ Do not aerate sharply when transporting fry; if gas bubble disease is found, immediately change the water or add fresh water;
⑤ When fish are found to have gas bubble disease, immediately add new (clean) water to the pond, and at the same time discharge part of the old water, or move the sick fish into clean water; mild cases can gradually return to normal, especially those caused by oxygen supersaturation, which recover easily;
⑥ Evenly splash salt water into the fish pond where gas bubble disease occurs, at a dosage of 3 to 5 grams of salt per cubic meter of pond water; generally it takes effect after several hours.
Gas bubble disease in fry is a common disease. In the early stage of the disease, the sick fish swim weakly at the water surface, and soon bubbles appear on the body surface, head, fin rays, gill filaments or inner intestine of the sick fish. When the bubbles are not large, the fish can still resist their buoyancy and swim downward, but the body loses balance, with the tail upward and the head downward, swimming and stopping intermittently. As the bubbles enlarge and the fish's strength is consumed, the sick fish float at the water surface and cannot sink, until death.
So why do fry suffer from gas bubble disease? Ponds for raising fry must be thoroughly cleared before stocking; generally quicklime (125 kg per mu) is used for disinfection, followed by a period of sun-drying. However, after sun-drying, the pond bottom is very loose, and after filling with water many small bubbles are produced; if fry swallow them by mistake, gas bubble disease is caused. Therefore, before fry are put into the pond, a fishing net or a thick long wooden pole must be used to pull back and forth several times in the pond; the water quality must be kept fresh and must not be too fertile.
It is worth noting that manure must be fully fermented before being applied to fry ponds. This is because manure that is not thoroughly fermented will slowly decompose after being applied to the fish pond, consuming oxygen in the water, while also continuously releasing methane and hydrogen sulfide gases that form extremely small bubbles, which are easily eaten by mistake by fish and cause gas bubble disease.
When gas bubble disease occurs, a two-pronged rescue measure should be taken for the affected fry: first, quickly add fresh water; second, for each mu of pond, use 4 kg of crushed gypsum, 4 kg of fresh tender Asiatic plantain, and 5 kg of soybean, soak them in water until swollen, grind them together into a slurry, and splash it over the whole pond, once every 2 days. After splashing 4 times in this way, the sick fish recover.
Now it is again the season for winter stocking of fingerlings. Although winter stocking of fingerlings has many advantages, it must be noted that if the dissolved gas in the pond water is overly saturated, or bubbles are continuously produced in the pond water and are swallowed by mistake by the fry, gas bubble disease is likely to occur. In production, the following methods can be used to prevent and treat gas bubble disease in fry:
① Keep the water quality fresh and control the amount of phytoplankton in the pond water so that it does not reproduce excessively;
② Before releasing fry, remove excess sludge from the pond, do not apply organic fertilizer that has not been fully fermented and decomposed, correctly master the amount of fertilizer and feed, and promptly remove decaying matter in the pond;
③ Groundwater introduced into fry ponds must first undergo full aeration;
④ Do not aerate sharply when transporting fry; if gas bubble disease is found, immediately change the water or add fresh water;
⑤ When fish are found to have gas bubble disease, immediately add new (clean) water to the pond, and at the same time discharge part of the old water, or move the sick fish into clean water; mild cases can gradually return to normal, especially those caused by oxygen supersaturation, which recover easily;
⑥ Evenly splash salt water into the fish pond where gas bubble disease occurs, at a dosage of 3 to 5 grams of salt per cubic meter of pond water; generally it takes effect after several hours.