The handling methods after a betta fish dies mainly include removing it from the water in a timely manner, examining the cause of death, and dealing with the remains. Firstly, once a betta fish dies, it should be removed from the water promptly to prevent it from rotting in the water, which could lead to water pollution and then affect the survival of other fish. Secondly, it's necessary to examine the cause of the betta fish's death to determine whether it was a natural death or due to diseases or other reasons. If the death was caused by a disease, further measures might be needed to treat the water quality or take other actions.

The possible causes of a betta fish's death may include water quality problems. Water quality issues are one of the main reasons for a betta fish's death. Therefore, it's very important to check the water quality regularly. Special testing equipment can be used to examine indicators such as the pH value, hardness, and temperature of the water to ensure that the water quality is suitable. If any problems with the water quality are found, adjustments should be made in a timely manner to avoid similar situations from happening again.
The living environment and health condition of betta fish are crucial to their survival. Betta fish are prone to situations like remaining motionless, sinking to the bottom, floating still on the water surface, and even dying due to water quality problems. Therefore, regularly changing the water, adjusting the water quality, changing the frequency of water changes, or adding a filter are effective ways to avoid the death of betta fish. Besides, observing changes in the behavior of betta fish, such as a decreased appetite and slow reactions, can also help to detect and deal with health problems in a timely manner.