Fin rot refers to a number of bacterial and fungal infections that can cause a betta fish to lose fins, said Dr. Ireifej. Poor water quality is the most common cause, along with a tank that is too ...

It’s Not Normal for a Betta Fish to Lose a Fin – Here’s How You Can Prevent It 7 May, 2021 ... Either fin rot (which is caused by an infection) or fin loss (caused by external factors) ...