1. Estrus: Sapphire fish may be in estrus when they bite other fish all the time. If there is no heterotype of the same kind in the fish tank, they will chase other heterosexual fish. Sapphire fish also spit out bubble nests during estrus, and breeders can observe whether there are many bubbles on some water surfaces.

2. Snatching food: Sapphire fish are irascible, and if they don't have enough food, they will also fight with other fish. They are quick and lively, and they can easily snatch the food of other fish into their mouths.

3. Play with each other: Sapphire fish are lively. If they keep chasing other fish and biting them, they may be playing games with other fish. If they are not seriously injured, the breeder may not have to stop them.

Sapphire fish be polybred. Although they are irritable, as long as there is enough space and food for breeding, there will generally be no big problems. When raising artificially, you can choose some fish with similar body shape to mix together. For example, map fish, parrot fish, pineapple fish, warship fish, colorful fairy fish, Luohan fish and so on. These kinds of fish and sapphire fish are similar in size, and have certain aggressiveness, which can be equally divided with sapphire fish.