# Aggressive behavior in Discus fish??



## shodoshi (Dec 15, 2010)

Perhaps someone has an idea - 

I have a 55 gallon tank with assorted fish. The water levels are excellent, I have a UV sterilizer, and the fish seems happy....except for the two discus. I have had the discus for four weeks and until this evening they looked like a bonded pair. This evening I started to see one of the discus chase the other. I have no idea of the sex of the fish. I don't know if the fish is being territorial because it might be close to mating season and it's standing it ground in the event a female comes into the tank. 

Thoughts?

TIA


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## phys (Feb 4, 2011)

make sure the water parameters for the discus are good.. Also, do you know what type of discus? maybe these will help determine if they're male/female. A new method for sexing discus
Discus'O'Zest >> The way I sex my Discus!

They're supposed to be schooling fish so i'm not sure why it'd pick on the other, other than to show dominance.


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## WhiteGloveAquatics (Sep 3, 2009)

Phys, Im glad that new method for discus sexing is getting around. 

This method has proven itself to me as I have been able to pin point the males from the females and then see one of each(in my case 4 of each) go into spawn.
I have a 210g tank and have 4 unproven pairs of discus that deposit eggs in this tank. total of 20 discus and over 75 tetras not to count bottom feeders.
I havnt noticed much aggression other then the occasional pecking order spat or a spawning site, thats it. Mine range from 3.5"-6" in size.


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## NeonShark666 (Dec 13, 2010)

Like many Cichlids, each Discus has its own personality and some are much more agressive than others. Did your fish source tell you they were a mated pair? Since Discus are almost impossible to by humans you don't know what the sex of your fish are. Cichlid males often fight for territory so you may have two males. You may also have a mated pair and they are having a "lovers spat". Make sure there are lots of tall plants in their tank so the one who is being chased has somewhere to hide.


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## Dottie B Woods (Jul 16, 2018)

I have 6 discuss fish. One, who we thought was one of a mated pair, has started approaching other discus and swimming flat horizontally while the other fish picks at him. Is this sexual behavior? We have checked the ph and temperature. We have had mating pairs in the past, but never saw this behavior before.


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