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Discus Bullying and Aggression

by | Mar 11, 2019 | 17 comments

When does Discus Aggression or Discus Bullying take place and what can you do to reduce it?

There is a “King Of The Hill” behavior that’s going to happen immediately when people receive our discus and place them into the tank. Once the fish calms down, relaxes, and once they relieve themselves from the stress of the trip, they immediately start creating their own pecking order.

Identifying Discus Bullying

The king of the tank behavior manifests itself in such a way as to say to the other discus “You can’t come near my area” and so on and so forth. Normally, it’s just a one-time incident where the rules are being laid. Meaning “I’m the king, you are the colonel, you are the sergeant, you are the captain and so on. It might not be in that order, but everybody knows what their rank is at the beginning. It’s very aggressive at first and a lot of our clients get very, very worried. Once this initial behavior is over, and the pecking order is established, the only time you’ll see aggression again is during feeding time. During feeding time is when you may notice the top dogs go up to eat first and then the rest of the discus will afterward.

Reduce Discus Bullying During Feeding Time

Now you have to be smarter than them. Don’t just put the food in one area, spread the food around the tank. Once you spread the food around it’s impossible for the biggest discus in the tank to patrol the whole area, so everybody gets a chance to eat. If he decides to go to the left of the tank and attack the food, the other discus will eat from the opposite side. If you just throw one lump of food in the tank, the king is going to guard it. He’s not even going to eat and he’s definitely not going let anybody else eat either. So plan it out accordingly and be the psychologist. Be the one in control during feeding times.

Changing Environment To Reduce Discus Bullying

Aggression can also happen during breeding times and when you’re tank is underpopulated. An example of an underpopulated tank is a 30-gallon tank with only two discus in it. Naturally, one discus is going to bully the other one. There’s nowhere for the smaller discus to run, so the smaller discus has a bullseye on it all day long in that particular case. But with three discus the aggressive one is going to try to go after both of them and wear himself out. The same thing is going to happen in a bigger tank. If you give the big discus fish too much space to patrol, he will only guard a portion of the tank and not chase the others continuously. Another strategy is to move stuff around in your tank to break up the monotony and territory.

Adding More Fish To Reduce Discus Bullying

Another solution is to add more discus to your tank. I don’t want you to overcrowd the tank but having a number of discus the same size will eliminate a lot of the bullying. Sometimes one discus becomes so aggressive you have no choice other than to separate that particular fish. This will often reset the pecking order and relieve some of the bullying in the tank.

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Wattley Discus Admin



    I had a few discus that stopped eating because of the bullying and grew weak and actually died. What can I do in such situations?

    • Arthur

      The only choice there is to separate them with a divider or into separate tanks. The change will cause a little shock to one or both fish, but it will wear off in about a week and it’s a better choice than death by bullying. Discus are so incredibly sensitive to EVERYTHING.

      • Wattley Discus Admin

        The divider will work. Sometimes separating them is the only solution with a major bully.

        • Paula belitsky

          I have two discus that have co-habitated beautifully until recently. The one fish is now u mercifully chasing, pushing the other one and corners it. Could this be a mating ritual?

          • Gabe Posada

            Hey Paula, I don’t think so…normally we recommend 4 or more discus together. This will create a normal pecking order and limit the excessive bulling of one individual discus.

    • Bella Danel McCartney

      Hi, I got a 260 juwel vision with 3 golden algae eater, 1 Panaque L239, 18 tetras, 5 discus (2 dark angels, one checkerboard, solid fire and blue diamond), 3 clown loaches ( small) and few tiny snails, parameters are great. Wormed and carbon applied, blue diamond is smallest about 5cm and others are from 8cm to 10cm or so. The alpha is solid fire (biggest) seem to fancy checkerboard 2nd biggest. My concern are blue diamond is being bullied by all especially during feeding time, we tried to put in different area but 4 was chasing him away, it now been 4 days since he last ate, he is still a baby and I am very worried because he is my baby I am attached to, checkerboard and Panaque are my babies as well, and the rest are my mum’s. We bought a divider to separate the bullies and blue diamond when we put it down he froze for long time. We took it out because we thought it scaring him, he started to move about but hide most time. He used be full of character and happy but past few days he just changed. Almost everyday we go to fish shop, explained and we did everything to find solutions. What can I do to help Waterford to eat and bullying stop! I am adding one more discus in January that when more discus comes

  2. Homer Gardin

    The smallest one in the tank is definitely the bully! I’ll try the scattering food on opposite sides method. As always, thanks!

  3. Alysha

    i have three discus atm just got them one of them chases alot i think one might be a male and the one that chases seems to want the male to itself not sure i’m if that’s right but its really singling out just the one about to buy 2 more discus hope that can reduce the aggression do you think 5 is ok for a 300L tank? Thanks

    • Wattley Discus Admin

      Discus usually do much better in groups of 6 or more. Depending on how many other fish you have in the tank I would suggest more discus of the same size.

  4. Laurie

    I Got some new discus and they started bullying one of my original discus to the point he would hide and keep his fins clamped .I moved him out of the tank it’s been 4 days he still will not eat and still has his fins clamped .the temp in that tank is 86 I did a partial water change on the second day.anything I can do to stimulate his appetite. I have tried all his favorite food and even put some garlic gaurd on his beef heart still nothing. He is currently with just a few endler guppies

    • Wattley Discus Admin

      Hey Laurie,
      I am assuming the pH is the same in both tanks. I am also assuming your water parameters are good. I would do daily water changes for a week and keep the lights dimmed and temp at 87. Also, if you can provide live food (black worms) even better. Sometimes it takes a while after changing their environment to bounce back. New tank size could also be an issue if it is much smaller.

  5. Muhammad Zahid

    I have six discus. 4 DISCUS chasing each other and they eat they own way…2 discus can’t fight . I separated them for 10days after that today I realized I discus at night but when I gave then food in the morning after that all fish TOGETHER bullying him and now he can’t eat today
    In that case what should I do?
    Please help
    Thanks in advance
    I m a subscriber of your channel.

    • Wattley Discus Admin

      Thanks for Subscribing!

      It depends on tank size, other community fish, and how many total discus fish you have.
      If you separate them for a time and bring them back to the same situation the bullying will start up again over time.
      Add more discus fish or change something in the tank so the agressive discus is not able to keep bullying the smaller ones.

  6. Diego

    Recently found you and Wow am I glad for your youtube channel and the advice you give in it!

    So I’m a School Bus Driver who got blessed recently with 4 gifted beautiful German discus in an established 120 gallon tank with sand and some driftwood. The previous owner just didn’t have enough time to look after them so he decided to look for someone with more time and a willing heart to look after them. I have about 15 years experience with tropical fish yet never with discus.

    I Had them in quarantine in a 20 gallon for 4 weeks and everything seemed fine. Some pecking order at lunch time. I also got 2 extra discus which I quarantine separately for about 2 weeks. I setup the 120 bare bottom with a thick decoration like tree in the middle with bubbles coming out of the middle for oxygenation in order to keep the tank in better conditions. I added all 6 at the same time yesterday 3 males and 3 females.

    Today I noticed quite some of that pecking order you mentioned about. I noticed is not only the males going at it but also the females. Question is for how long should I expect this behavior? Should eventually try an add an extra female to offset the balance in the numbers? Any advice is welcome as never in my wildest dreams did I thought I would have a chance to own such beautiful creatures…

    • Wattley Discus Admin

      Hey Diego,
      Sometimes adding a few more fish will distribute some of the aggression.
      Over time the normal pecking order should be set and you should notice a change.
      The main issue to keep an eye out for is if those lower in the pecking order stop eating.

  7. Charlotte Lindsey

    Wanted to add that I do water changes every other day or for sure by the third day .. live in Hawaii and they have done fine for an extended period of time in their tank and water .


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