Discus fighting
When discus fights it is the manner to show you what they feel, what they want, what they complain etc.
You then must find out what are actually the matters. You have to stop them fighting. Otherwise, they will get hurt and stress. Finally they will get sick. Bacteria will spread. Epidemic breaks out in an aquarium. It will lead to the death of all the fish. You must find out what is the cause. The following could be one of the reasons.
1. Mating
Congratulation! Your babies tell you that they have grown up. They prefer to live in pair. You will have to separate them from others. If you have three in the tank, they will attack they other one. Remove the odd one. Otherwise the couple will kill them. If you have many in the tank, remove the pair
2. Newcomer - Introducing new discus into tank
If you have introduced new fish to the tank, sometimes they fight. Existing discus fish will guard their territory and fight. Remove the fighting fish to other tank. Make him the newcomer.
When you introduce the new fish to the tank, the best time to do it is at night. Existing discus don't notice it that the new comer has come to the tank. Do not introduce one fish alone, surely she will get bitten.
3. Bully
The big fish will fight the small fish. Try if possible keep the fish of same size together in one tank.
If there is only one bully, get him out temporary, then return it to the tank, make him a new comer.
4. Fight after spawning
The fish become very emotional after spawning. Sometimes they will fight. Cover the eggs immediately with the wire mesh. After removing the fry, they will also fight. They complain where are their babies? They have the parental love over their babies. They feel sad when their babies disappeared.