Here's why:
* Territoriality: While not as aggressive as males, female bettas can still exhibit territorial behavior, especially when confined to a small space.
* Competition for resources: They can compete for food, hiding spots, and even the best position in the tank.
* Stress and injury: Constant aggression can lead to stress, fin nipping, and even serious injuries.
However, there are exceptions:
* Larger tanks: Providing a large enough tank with plenty of hiding spots, plants, and ample swimming space can reduce the chances of aggression. A tank size of at least 10 gallons is generally recommended for multiple females.
* Careful selection: Choosing females that are known to be peaceful and have compatible personalities can increase the chances of success.
* Introducing slowly: Introduce females slowly to allow them to adjust to each other's presence. Observe their behavior closely and be prepared to separate them if aggression occurs.
Alternatives to keeping multiple females:
* Sorority tank: A sorority tank involves keeping a group of female bettas together, but it requires careful planning, a larger tank, and constant monitoring.
* Individual tanks: Providing each female betta with their own tank is the safest and most stress-free option.
Remember: Even if you manage to keep multiple female bettas together successfully, it's important to closely monitor their behavior and be prepared to separate them if necessary.