Why do Discus fish get aggressive ?

Discus fish are know as a peaceful type aquarium fish. This is only half true. They might be peaceful with other type of fish but among them selves they can get pretty aggressive. If you have a bunch of Discus fish you might notice fighting break out here and there. Interesting thing is sometimes even smaller Discus fish fight with bigger Discus fish without backing away. One good thing is unlike other aggressive Cichlids types these fights are not savage. So most of the time you dont have to interferer. Specially in feeding times you might notice they get aggressive. How to keep aggression to a lower level ?

• Discus fish are Cichlids. So they can get extremely territorial . Too many fish in a smaller tank can build up aggression pretty quickly. Some Discus fish experts say there should be 10 Lt. of water for each fish. Bigger the tank get less will be the aggression.
• You need to keep at least 6 Discus fish together. So their aggression would spread out. Otherwise smaller fish can get stressed by bullied by big Discus fish too often.
• Aggression can be increase when temperature rise up. Because fish get more active and also they get hungry faster.
• Also when a pair try to mate. After they pick a place for eggs then can become aggressive to any fish who comes near.

One important thing to remember is you can keep a single discus isolated because he get bullied by others. Discus are a social fish. They stay in groups isolating a Discus would make him more stress or shy.