* Aggression: Male fighting fish are incredibly aggressive towards each other. They are bred for fighting and will see another male as a direct threat. They will aggressively attack, potentially injuring or killing the other fish.
* Territorial: Even females can be aggressive towards each other, though not as intensely as males. They have a strong territorial instinct and may fight over space and resources.
Exceptions:
* Separate tanks: The only way to keep two fighting fish together safely is to keep them in separate tanks.
* Experienced breeders: Some experienced breeders can successfully house multiple male bettas together, but this requires specialized knowledge, careful tank setup, and constant observation. This is not recommended for the average fish keeper.
It's important to remember that:
* Even if the fish seem to get along at first, aggression can erupt at any time.
* Even if one fish is larger or more aggressive, the smaller fish can still be severely injured or killed.
The safest approach:
* Keep male fighting fish individually.
* If you want to keep multiple females, do your research and be prepared to provide a large, heavily planted tank with plenty of hiding places.
* Always monitor your fish closely for signs of aggression and be prepared to separate them if necessary.