It has been raised for one year 15 cm, indicating that the water quality has always maintained a living environment suitable for grass gold.
Bending means that you must have been greatly stimulated before you die, leading to muscle atrophy.
Sink into the bottom of the box after death instead of floating or fluttering in the water, indicating that the oxygen inhaled by the float is less than that exhaled.
According to the above conditions, the causes of diseases caused by water quality environment are discharged, leaving the internal invisible reasons. Simple analysis should be caused by excessive outbreak of parasites in the body, so it is a symptom of muscle twitching and bending after death, and because muscle twitching can not breathe and filter oxygen normally, there is less air floating in the water and it sinks to the bottom.
As for when the amount of parasites in other fish will break out and lead to the same situation, it is difficult to judge. Prevention is the main thing, so buy a bottle of fish medicine and send it inside. Or feed and scrape a little intestinal worms these two days, so that the fish will have diarrhea and discharge too many parasites. Drugs that kill parasites have side effects, so don't use them easily unless you have to, because using them in large quantities will kill fish.