Fighting fish are popular among customers, but they are difficult to keep because they constantly fight each other. Therefore, we keep them separately, even using thick paper to block their view of one another.
Once, a staff member placed a fighting fish into another tank. The other fish attacked it as a group, and by the time I noticed, it was nearly dead. I immediately moved it to a separate tank for recovery.
Tom once told me a bloody story about fighting fish. The male creates a nest of white bubbles on the water's surface to lure the female into laying eggs inside. After she lays her eggs, the male kills and eats her. He then guards the eggs, waiting for the fry to hatch and grow. Once the young fighting fish mature, they kill and eat their father.
If this is true, it's truly brutal!