Why when introducing a new Discus fish to my discus aquarium,the discus fight with the new arrival and it get stressed and would not eat a thing.
This is the behavior of the discus. You have in you tank a bullu, a leader and an aggressive discus. When they react they behave quite naturally. They will fight. This is what they normally do. It’s normal.
When you introduce the new fish to the tank, the best time to do it is at night.
They don’t notice it that the new comer has come to the tank. Do not introduce one fish alone. Sure she will get bitten.
If there is only one bullyy, get him out temporary. Then return it to the tank, make him a new comer.