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The 5 Most Common Discus Ailments and How To Cure Them

by | Feb 10, 2019 | 38 comments

Hi guys, welcome back to the Jack Wattley Discus hatchery. I’m Gabe Posada, and this is a general overview of the most common ailments we see in the discus fish, and how to cure them.

The Most Common Ailments 

Today we are going to talk about five of the most common ailments a discus can get and how to cure them. We will also be looking at some of the symptoms and side effects of each ailment so that you can better identify and determine what it has, and how to treat it. Obviously, you’re not going to swallow an oxydoxycycline to cure a headache, so we want to give you the right information and medications so that you get it done properly and everything works right the first time.

Internal Parasites

The first one we’re going to talk about are internal parasites. Internal parasites are primarily cause by Hexamita, small intestinal parasitic diplomonads. hexamita can be caused by many factors, the main causes being stress or the fact that the fish ate something that was loaded internally with a hexamita. The most common symptoms and identifiers that your fish may have this parasite is when the discus is pooping white, they have a hole in their head or they’re thinning out even though they’re eating.

If you see any of these indicators, the best solution is metronidazole. There are many ways of treating with metronidazole, some will say do a treatment every eight hours for 3 days because the shelf life for metronidazole in water is exactly eight hours. After eight hours, there’s likely nothing in the water left to treat. Here at Wattley Discus we like to take it up 10 days rather than three days every eight hours to be on the safe side and ensure no parasites return. To administer this treatment, we use one gram of Metronidazole for every 20 gallons of water. You can mix it into a cup of water outside of the fish tank, and then pour it right in.

If your discus is eating, then what you want to do is hold some of it into the food and give it to them for 10 days straight. This will clean them out and it will prevent any hatchlings, or anything being born that is immune to the medication while it’s in the reproduction stages. It is important to be on the safe side when deciding how long you want to administer this treatment for because if you take it to five days and then the six day they started to hatch, then you’re back to square one.

 Very rarely do Discus fish get tape worms or capillaria, which are other forms of internal parasites. Those two must be treated with praziquantel, but we aren’t going to get into that here because hardly ever comes up.


Cloudy Eyes

Another of the most common ailments that we often hear about is cloudy eyes. The number one reason for this is that they experienced some sort of physical trauma to the eye. Maybe the fish were arguing and one attacked the others head, they scratch themselves on something, or got startled.

Furthermore, if your tanks Ph balance all the sudden crashes, this will also cloud the eyes. Luckily, the eye has a protective layer that will take the burden so the entire eye is not lost. In most cases, a little bit of salt and a tiny stress coat from API that has Aloe Vera in it will help get this resolved and you’ll start to see it heal and the white circle will start to disappear. If you don’t catch this early enough, however; it is possible that the fish may lose its eye.


Fin Rot

Next up is fin rot. Now, to preface this let’s consider a normal external bacterial infection on a human. If there’s an external bacterial infection, the first thing that’s going to be affected are the extremities, your fingers, hands, etc. It’s not going to go straight through your skin and hit your liver. It is the same for Discus fish and that’s why you start getting that fin rot. If that happens, it is usually caused by a high organic load.

The only way you’re truly going to be able to determine this is with a microscope, and for somebody to analyze your water. We’re not going to get that technical. If you see the fin rot coming on and the fish starts to look like a sunflower because it’s starting to lose its fins, it means that there’s a buildup of anaerobic bacteria in your gravel or somewhere that’s now coming out of the gravel and attaching itself to your fish.

In this case, we need to use Oxytetracycline. Keep an eye out for this on our website, as we are working on adding it to our selection soon. This is the best way to resolve cloudy eyes and keep your tanks clean. Make sure that if you’ve got any kind of wood or rocks in your tank, clean very well around it because these things are breeding ground for all kinds of bacteria.



The last ailment we are going to be talking about today is bloating. Bloating is a common ailment that happens even to us. What causes this is when you eat something and it spoils inside your stomach before your digestive system can break it down, and as a result fills up the stomach with gas.  The number one cure for this in discus fish is Epsom salts.

When administering, you need to use one tablespoon for every 40 gallons of water. Epsom salts do not go away once added to the tank and will stay in the water until you change it, so you don’t need to replace it unless you do a water change. Once you put the Epsom salts in you need to bring your temperature up to 86 or 88 degrees because this will speed up their metabolic rate and get everything out of them. Going back to our example of bloating in humans, Epsom salts is basically just ex-lax for fish. Be prepared after administering the salt to your tank because it will make the fish poop beyond recognition.

Now, the second thing you need to do after the Epsom salt, if you get them to relieve themselves, is you want to add a mild treatment of metronidazole just in case some hexamita developed from the fish’s excrement, so you don’t end up with internal parasites.



 These are some of the most common ailments you will find in discus fish. We experience these problems here at Wattley Discus daily and know what it is going to take to get the results you want. Hopefully you are maintaining your tank and you’re never going to see any of these, but if you do, reference this article for some quick remedies.

If you have any questions, just keep them coming the way you have been! I realized that we only go into general detail here, and that’s because we don’t want to make these articles too long. If you ever have any specific questions though, we are here to help. We truly appreciate the fact that so many of you are sending us thank you notes on Facebook, by email and are calling us up. We thank you and appreciate the fact that you’re reading our blog and we will continue to bring you even more helpful content in the future!

And once again, thank you for coming and joining us at the Jack Wattley Discus hatchery.

author avatar
Wattley Discus Admin


  1. Froilán

    Great article! Thank you so much

    • Lisa

      I have two discus in my 30 litre tank
      They were always at the front waiting to be fed.
      Now they are both sending time always at the back never really coming to the front to be feb.
      I have a lot of driftwood and a lot of hiding places
      The smaller one I do see on a daily basis.
      But the larger one has been a phantom for a while
      To my horror tonight showed himself with his rib cage showing and a lot of his tail missing
      What the hell
      I don’t want it to suffer
      What I’m I doing wrong
      Water changes when it needs it
      Carbon as needed
      Decent food
      And I proper air flow

      • Wattley Discus Admin

        Could be an injury.
        Carbon not needed in filter as there is no carbon filter in the amazon. As long as you do a 20% water change per week.

  2. Richard Taylor

    A video idea if not done already, is how to get pairs to spawn again after they have stopped awhile.

  3. Jeff Stadelman

    What about when the fish suddenly stop eating? I’ve lost a few that did that and over time got super skinny and finally died. All other fish were super healthy.

    • Gabe Posada

      Same principal. If you stop eating it is because you have an internal problem. Fish need to be isolated and dewormed.

  4. Viviana tovar

    Thank u… From Colombia.

  5. Richard

    I would like to see a video on how to set up. A tank for discus.

  6. Steve Heller

    Can you treat Epsom salt and metro at the same time or is it recommended to treat Epsom then metro separately

  7. david

    need help please message me thanks wana save these discus

  8. Jan Kocar

    Dear Gabriel.
    I was watching all your videos with great interest. I have tropical fish farm in north Queensland/ Australia producing tropical aquarium fish (about 1 000 000 / year). I don’t encounter many diseases because my system is running on water in water out. Similar like production of trout in northern hemisphere. I also try to get as much oxygen in the water as possible. Could you
    please let me know where to purchase your Ventury valves mounted above your tanks as I didn’t encounter it here in Australia. Your help would be very much appreciated.
    Thank you very much in advance. Please excuse my English as it isn’t my first language.
    Regards Jan Ikan Pty Ltd

    • Gabe Posada

      On Alibab just punch in Mazzi Venturi

  9. Sally

    Great big white lump on the face of discus help what is it

    • Gabe Posada

      Use the Metronidazole treatment for 10 days.

      • Mustafa

        Ten days continue one gram each day in twenty gallons water change. Is that ok please.

  10. sheila demorrow

    Gabe, this isn’t about illness but I tried to contact you about getting a pair but not until mid-February. Do you always have pairs? If not can I send 100.00 dollars and the rest on Feb 14th? I have had Discus for a few years but I can’t ever seem to get a pair. I have 5 large Disus in 60 gallon and med. to large Discus in a 75 gallon. They are all over 2 yrs old. I really want a pair and I love your Discus. Thank you Sheila Demorrow. I live in Texas also. Any ideas?

    • Gabe Posada

      Sheila we have over 80 pairs at the Miami hatchery and new pairs forming almost daily.
      When you are ready just let us know.

  11. sheila demorrow

    Thank You!!

  12. Jonathan Krupski

    How do you do the 10 day treatment using api general cure for discus? What’s the step by step? Is it different than the package suggests?

  13. sheila demorrow

    Hi Gabe, this is Sheila Demorrow again. I will be ordering the red melon pair on this Wednesday the 13th. I have got my 30 gallon painted light blue everywhere but the front. Our tap water is bad so I only use a little to help with ph. I use a filter system with the RO filter too. That water is about 20 TDS and a low ph. I will use a neutralizer to bring the ph up to 7.0. Since I have never had a breeding pair then what should my water perimeters be? I have a 75 gallon with 7 discus and a 60 gallon with 5 large discus. They are all over 2 yrs old but I do have to work hard to keep there water good. They are both bare bottom. I use 2 hang on the backs. 2 sponge filters in tank and a canister filter. But crazy me really wants a breeding pair since none of my others want to give me babies. Should I take one of my seeded sponges out and put in breeding tank? Do I need extra filtration? I’m just nervous about getting it right? I will be getting back with you but I want the tank ready. Thank You Sheila Demorrow

  14. Nicholas Dsouza

    Hi Gabe,

    I have 2″ and 3″ discus in a 56 gallon tank. I do 2 water changes daily and add a handful of rock salt each time. Is there anything wrong I’m doing as I read a lot of mixed opinions online.

    • Gabe Posada

      Discus are fresh water fish. They only require salt when dealing with a bacterial infection.
      No one spreads salt in the amazon river where your discus came from. Use common sense.

  15. Mustafa

    Hi Gabe
    I always watch your videos and learn lot of thing from there i am very very helpful with that and happy as well , if i need any instant help how i contact with you . I have 12 proven pairs discus and they are pretty big sizes and very healthy,age two and half but recently stop lay eggs and stop eating food i feed them beef heart so any advice for me please.

  16. Christos

    Metronidazole is flagyl right?I can find only flagyl pills of 250mg and 500mg.What is the dosage if i have the 500mg.You say 1gr per 20gallons but with what effectiveness ?
    Thanks in advance for your answer and for the very helpful videos you upload to all of us.Keep up you are excellent.

  17. Shika

    Hi Gabe

    During 10 days treatment how to change water? Should we feed fishes? is there any effect for fish’s organ during10 days treatment?


    • Gabe Posada

      Whenever you want to do a water change you can, but always after 8 hours of treatment.
      Yes there is an affect, they will all be dewormed.


    when using epsom salt treatment, how long should the discus fish be kept in the water with epsom salt?

    • Wattley Discus Admin

      Epson salt treatment should continue until the fish relieves itself. As you do water changes repeat the process until the constipated discus is relieved.

  19. Linda

    What do I do about a discus that seems to have quite an open wound. It seemed to happen over night. It looks like some of his flesh is hanging out the hole. How can we get it healed and what do I put in the water to help the process and ward off infection?

    • Wattley Discus Admin

      Do you have Plecos? Sometimes they may have caused the problem.
      Some Plecos (which we do not carry) can get agressive towards discus fish. They are nocturnal so at night they may be causing the problem.
      For basic healing I would try Seachem StressGuard Slime Coat Protection

  20. Marcus

    Hi, I’ve got a few fish that I have kept for a few months don’t have any clamped fins and have an appetite but are constantly hiding in the corner and are easily startled. Have you got any suggestions on whether these fish need any treatment? Many thanks

  21. Zack

    Why is my blue discus turning black and looking thin how can I treat it

  22. Ben

    Treating discus fry?

    2 lovely breeding discus in a 60L tank – around 50 healthy 2-week-old swimming fry feeding well and happy. The issue I have is the Male discus is not eating at all. It has been around 4 weeks since I have seen it consume any food now, it looks slightly pinched in the stomach and just sits at the bottom of the tanks looking sorry for itself. (tried bloodworms, beef heart, pellet, flake and the pellet bloodworm-looking type all its favourites)

    The female feeds every time the lid is open the water changes daily and all water parameters are on the button. I have dropped in some salt tonight and she has moved around somewhat but is it safe to treat the whole tanks with NT flukes and worm treatment for them all? or is this something different? I can see 2 small white patches on the lower fins that are closest to the floor if this helps and it is a clear bottom tank with good external filtration.

    I don’t want to disrupt unless I have to the tank and stress them out by removing them if I don’t have to, but this has been my 7th attempt at the fry and so far they are doing fantastic and I’m the furthest I have ever been. I’m just worried about this parent.

    P.S. Your YouTube videos are awesome and the content is perfect! very useful.

    Thank you in advance


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