The gills of the fish turn white and the gills gradually fall off. When the Hexagonal Arowana dies, its gills will gradually turn white, the gills will gradually fall off, and the body of the Hexagonal Arowana will float on the water. The water must be changed in time and the water temperature should be maintained at about 15 to 25°C. In addition, hexagonal arowanas can kill each other, so it is best to keep them alone.